diff --git a/AGENTS.md b/AGENTS.md
index 266618122..ca152fe7c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -273,7 +273,7 @@ stops startup instead of leaving a healthy-looking partial schema, and
 application code must not compensate for a missing table.
 
 Period leftover pairs (ADR 0017 / 0018 / 0048 / 0049 / 0119 / 0158 / 0162 /
-0163 / 0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273) are computed in `lineageweave/leftover_pairs.py` from the
+0163 / 0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274) are computed in `lineageweave/leftover_pairs.py` from the
 residual after a real GRM/GPCM score, never invented. Distances are
 Euclidean on the two-dimensional Gabriel leftover map; missing cells stay
 out of the factorization. Closest and farthest post–criterion pairs
@@ -309,7 +309,11 @@ coordinates. ADR 0273 captions leftover-map pair segments with persisted
 leftover-map explained leftover share `e` so the pair-row `R̂²/R²`
 badge matches the graphic; a missing or non-finite `e` omits that
 explained leftover share caption and does not invent `e` from `R̂` and
-`R` or from plotted coordinates. When `R`, `R̂`, `U`, `x`,
+`R` or from plotted coordinates. ADR 0274 captions leftover-map pair
+segments with persisted leftover-map unexplained leftover share `s` so
+the pair-row `U²/R²` badge matches the graphic; a missing or non-finite
+`s` omits that unexplained leftover share caption and does not invent
+`s` from `U` and `R` or from plotted coordinates. When `R`, `R̂`, `U`, `x`,
 `s`, and `e` are finite, `e + s + x = 1`. When coordinates,
 reconstruction, and distance are finite, `R̂ = ξ · ζ` and
 `d = ‖ξ − ζ‖`. The pairs sit above the member
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index a071f7a8b..4569b175e 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -637,7 +637,7 @@ information at the group's mean θ (Lord, 1980 max-info CAT). Rankings
 persist to `report_item_information`. After those IRT main effects,
 residual SVD leftover pairs on two Gabriel axes (Jeon et al., 2021;
 ADR 0017 / 0048 / 0049 / 0119 / 0148 / 0158 / 0162 / 0163 / 0164 / 0168 /
-0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273) persist to `report_leftover_pair` with signed residual `R`,
+0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274) persist to `report_leftover_pair` with signed residual `R`,
 observed `Y`, expected `E[Y|θ, item]`, full leftover-map rank, unexplained
 leftover, ADR 0201 reconstruction evidence, ADR 0185 cross-share evidence,
 ADR 0233 unexplained leftover share `s`, ADR 0266 explained leftover
@@ -650,7 +650,8 @@ badge matches the plot. ADR 0271 captions leftover-map pair segments
 with persisted leftover-map distance `d`. ADR 0272 captions leftover-map
 pair segments with persisted leftover-map reconstruction `R̂`. ADR 0273
 captions leftover-map pair segments with persisted leftover-map
-explained leftover share `e`. Click a post marker or a pair button
+explained leftover share `e`. ADR 0274 captions leftover-map pair
+segments with persisted leftover-map unexplained leftover share `s`. Click a post marker or a pair button
 opens that post. Those ADRs are the normative mathematical, storage, and
 display contracts. Leftover-map axis share
 (Gabriel inertia of residual SVD axes 1 and 2; ADR 0148) persists to
diff --git a/CHANGELOG.d/2.31.0-leftover-map-segment-unexplained-share.md b/CHANGELOG.d/2.31.0-leftover-map-segment-unexplained-share.md
new file mode 100644
index 000000000..9560197a4
--- /dev/null
+++ b/CHANGELOG.d/2.31.0-leftover-map-segment-unexplained-share.md
@@ -0,0 +1,15 @@
+## 2.31.0 — Leftover-map unexplained leftover share on graphic-display pair segments
+
+- Caption leftover-map graphic-display pair segments with persisted
+  leftover-map unexplained leftover share `s = U² / R²` (ADR 0274). After
+  `make seed`, closest and farthest leftover pairs sit above the member
+  list with the Gabriel biplot of already-named coordinates, leftover-map
+  axis share when finite, axis ticks that match `ξ (x, y) ζ (x, y)` on
+  the pair row, pair segments that match `d` on the pair row, pair
+  segments that match `R̂` on the pair row, pair segments that match
+  `R̂²/R²` on the pair row, and pair segments that match `U²/R²` on the
+  pair row; click a post marker or a pair button opens that post. A
+  missing or non-finite `s` omits that unexplained leftover share
+  caption. A share greater than 1 is shown, never clamped. Do not invent
+  `s` from `U` and `R` or from plotted coordinates. Never invent a
+  leftover score. Never invent a theta. No new columns.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 271c89353..8c96e1431 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,21 @@ All notable changes to this project are documented here. Format follows
 
 ### Added
 
+- Period leftover pairs now caption leftover-map graphic-display pair
+  segments with persisted leftover-map unexplained leftover share
+  `s = U² / R²` (ADR 0274 / v2.31.0). After `make seed`, closest and
+  farthest leftover pairs sit above the member list with the Gabriel
+  biplot of already-named coordinates, leftover-map axis share when
+  finite, axis ticks that match `ξ (x, y) ζ (x, y)` on the pair row,
+  pair segments that match `d` on the pair row, pair segments that
+  match `R̂` on the pair row, pair segments that match `R̂²/R²` on
+  the pair row, and pair segments that match `U²/R²` on the pair
+  row; click a post marker or a pair button opens that post. A
+  missing or non-finite `s` omits that unexplained leftover share
+  caption. A share greater than 1 is shown, never clamped. Do not
+  invent `s` from `U` and `R` or from plotted coordinates. Never
+  invent a leftover score or a theta. No new columns.
+
 - Period leftover pairs now caption leftover-map graphic-display pair
   segments with persisted leftover-map explained leftover share
   `e = R̂² / R²` (ADR 0273 / v2.30.0). After `make seed`, closest and
diff --git a/CLAUDE.md b/CLAUDE.md
index c4dad11ee..1579f3ab5 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -49,7 +49,7 @@ cutoff. Global Ask optional `knowledge_cutoff` uses the same cover
 
 Create/start endpoint rules (ADR 0017 / 0021), tie-vs-miss similarity
 (ADR 0026), R&R catalog ids (ADR 0019 / 0027), leftover pairs
-(ADR 0048–0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273), occupational construct catalog search
+(ADR 0048–0164 / 0182 / 0185 / 0201 / 0233 / 0266 / 0267 / 0268 / 0269 / 0270 / 0271 / 0272 / 0273 / 0274), occupational construct catalog search
 (ADR 0257), the text-channel embedding swap and cosine
 clamp (ADR 0190), per-edge channel-score persistence (ADR 0195),
 token-backed status notices (ADR 0220),
diff --git a/docs/adr/0048-persist-lsirm-leftover-pairs.md b/docs/adr/0048-persist-lsirm-leftover-pairs.md
index 3c0adc8a5..6451f3ef6 100644
--- a/docs/adr/0048-persist-lsirm-leftover-pairs.md
+++ b/docs/adr/0048-persist-lsirm-leftover-pairs.md
@@ -16,7 +16,8 @@
 [ADR 0270](0270-leftover-map-coordinate-ticks.md) (leftover-map coordinate ticks);
 [ADR 0271](0271-leftover-map-segment-distance.md) (leftover-map distance on pair segments);
 [ADR 0272](0272-leftover-map-segment-reconstruction.md) (leftover-map reconstruction on pair segments);
-[ADR 0273](0273-leftover-map-segment-explained-share.md) (leftover-map explained leftover share on pair segments)
+[ADR 0273](0273-leftover-map-segment-explained-share.md) (leftover-map explained leftover share on pair segments);
+[ADR 0274](0274-leftover-map-segment-unexplained-share.md) (leftover-map unexplained leftover share on pair segments)
 
 ## Context
 
@@ -79,7 +80,9 @@ pair segments with persisted leftover-map distance `d`; it adds no
 columns. ADR 0272 captions leftover-map pair segments with persisted
 leftover-map reconstruction `R̂`; it adds no columns. ADR 0273 captions
 leftover-map pair segments with persisted leftover-map explained leftover
-share `e`; it adds no columns.
+share `e`; it adds no columns. ADR 0274 captions leftover-map pair
+segments with persisted leftover-map unexplained leftover share `s`; it
+adds no columns.
 
 Cascade the rows with `report_period_score`. A leftover post must
 also be a `report_member_score` row, and the leftover criterion
diff --git a/docs/adr/0049-leftover-pair-report-ui.md b/docs/adr/0049-leftover-pair-report-ui.md
index 39cca48bd..e60d13201 100644
--- a/docs/adr/0049-leftover-pair-report-ui.md
+++ b/docs/adr/0049-leftover-pair-report-ui.md
@@ -17,7 +17,8 @@
 [ADR 0270](0270-leftover-map-coordinate-ticks.md) (leftover-map coordinate ticks);
 [ADR 0271](0271-leftover-map-segment-distance.md) (leftover-map distance on pair segments);
 [ADR 0272](0272-leftover-map-segment-reconstruction.md) (leftover-map reconstruction on pair segments);
-[ADR 0273](0273-leftover-map-segment-explained-share.md) (leftover-map explained leftover share on pair segments)
+[ADR 0273](0273-leftover-map-segment-explained-share.md) (leftover-map explained leftover share on pair segments);
+[ADR 0274](0274-leftover-map-segment-unexplained-share.md) (leftover-map unexplained leftover share on pair segments)
 
 ## Context
 
@@ -47,7 +48,8 @@ when finite (ADR 0269). Leftover-map axis ticks name persisted `ξ` /
 `ζ` coordinates (ADR 0270). Pair segments name persisted leftover-map
 distance `d` (ADR 0271). Pair segments name persisted leftover-map
 reconstruction `R̂` (ADR 0272). Pair segments name persisted leftover-map
-explained leftover share `e` (ADR 0273). The pair renders every available finite measurement.
+explained leftover share `e` (ADR 0273). Pair segments name persisted leftover-map
+unexplained leftover share `s` (ADR 0274). The pair renders every available finite measurement.
 The next action uses the first available value in the priority below; no
 amendment hides another badge, rank 0
 explicitly names no leftover structure, and unexplained leftover names
@@ -84,6 +86,8 @@ Leftover-map reconstruction on pair segments is
 [ADR 0272](0272-leftover-map-segment-reconstruction.md).
 Leftover-map explained leftover share on pair segments is
 [ADR 0273](0273-leftover-map-segment-explained-share.md).
+Leftover-map unexplained leftover share on pair segments is
+[ADR 0274](0274-leftover-map-segment-unexplained-share.md).
 
 After `make seed`, closest and farthest leftover pairs sit above the
 member list. Click a pair to open that post with the leftover
diff --git a/docs/adr/0233-leftover-map-unexplained-share.md b/docs/adr/0233-leftover-map-unexplained-share.md
index ebbfe41b3..7d0a5efe8 100644
--- a/docs/adr/0233-leftover-map-unexplained-share.md
+++ b/docs/adr/0233-leftover-map-unexplained-share.md
@@ -4,7 +4,9 @@
 **Date:** 2026-08-27
 
 **Amended by:** [ADR 0266](0266-leftover-map-explained-share.md)
-(explained leftover share e)
+(explained leftover share e);
+[ADR 0274](0274-leftover-map-segment-unexplained-share.md)
+(leftover-map unexplained leftover share on graphic-display pair segments)
 
 Amends [ADR 0048](0048-persist-lsirm-leftover-pairs.md) and
 [ADR 0049](0049-leftover-pair-report-ui.md). Independent of leftover-map
diff --git a/docs/adr/0268-leftover-map-graphic-display.md b/docs/adr/0268-leftover-map-graphic-display.md
index 9182aab35..e13aad80a 100644
--- a/docs/adr/0268-leftover-map-graphic-display.md
+++ b/docs/adr/0268-leftover-map-graphic-display.md
@@ -12,7 +12,9 @@
 [ADR 0272](0272-leftover-map-segment-reconstruction.md)
 (leftover-map reconstruction on pair segments);
 [ADR 0273](0273-leftover-map-segment-explained-share.md)
-(leftover-map explained leftover share on pair segments)
+(leftover-map explained leftover share on pair segments);
+[ADR 0274](0274-leftover-map-segment-unexplained-share.md)
+(leftover-map unexplained leftover share on pair segments)
 
 Amends [ADR 0049](0049-leftover-pair-report-ui.md) and
 [ADR 0267](0267-leftover-map-coordinates.md). Independent of leftover-map
@@ -89,7 +91,8 @@ leftover-map axes when finite (ADR 0269). Leftover-map axis ticks name
 persisted `ξ` / `ζ` coordinates (ADR 0270). Pair segments name
 persisted leftover-map distance `d` (ADR 0271). Pair segments name
 persisted leftover-map reconstruction `R̂` (ADR 0272). Pair segments name
-persisted leftover-map explained leftover share `e` (ADR 0273). When coordinates, reconstruction, and
+persisted leftover-map explained leftover share `e` (ADR 0273). Pair segments name
+persisted leftover-map unexplained leftover share `s` (ADR 0274). When coordinates, reconstruction, and
 distance are all finite, `R̂ = ξ_{1:2} · ζ_{1:2}` and
 `d = ‖ξ_{1:2} − ζ_{1:2}‖` remain the same identities already
 persisted by ADR 0267.
diff --git a/docs/adr/0273-leftover-map-segment-explained-share.md b/docs/adr/0273-leftover-map-segment-explained-share.md
index 3330e3104..5fe4e4810 100644
--- a/docs/adr/0273-leftover-map-segment-explained-share.md
+++ b/docs/adr/0273-leftover-map-segment-explained-share.md
@@ -3,6 +3,9 @@
 **Decision status:** Accepted
 **Date:** 2026-08-29
 
+**Amended by:** [ADR 0274](0274-leftover-map-segment-unexplained-share.md)
+(leftover-map unexplained leftover share on pair segments)
+
 Amends [ADR 0268](0268-leftover-map-graphic-display.md) and
 [ADR 0049](0049-leftover-pair-report-ui.md). Independent of leftover-map
 reconstruction on pair segments
@@ -84,7 +87,8 @@ and `ζ`, leftover-map axes name persisted Gabriel inertia share when
 finite, leftover-map axis ticks name the same coordinates shown on
 the pair row, pair segments name persisted leftover-map distance `d`,
 persisted leftover-map reconstruction `R̂`, and persisted leftover-map
-explained leftover share `e`; click a post marker or a pair button
+explained leftover share `e`, and pair segments name persisted leftover-map
+unexplained leftover share `s` (ADR 0274); click a post marker or a pair button
 opens that post. Hidden posts stay hidden. Rank-0 unused axes still
 plot at the origin, still name zero leftover-map axis share with a `0`
 tick, still name `d 0.00` when that distance is persisted, still name
diff --git a/docs/adr/0274-leftover-map-segment-unexplained-share.md b/docs/adr/0274-leftover-map-segment-unexplained-share.md
new file mode 100644
index 000000000..bd26fd3d1
--- /dev/null
+++ b/docs/adr/0274-leftover-map-segment-unexplained-share.md
@@ -0,0 +1,132 @@
+# ADR 0274 — Name leftover-map unexplained leftover share on graphic-display pair segments
+
+**Decision status:** Accepted
+**Date:** 2026-08-29
+
+Amends [ADR 0268](0268-leftover-map-graphic-display.md) and
+[ADR 0049](0049-leftover-pair-report-ui.md). Independent of leftover-map
+explained leftover share on pair segments
+([ADR 0273](0273-leftover-map-segment-explained-share.md)), leftover-map
+reconstruction on pair segments
+([ADR 0272](0272-leftover-map-segment-reconstruction.md)), leftover-map
+distance on pair segments ([ADR 0271](0271-leftover-map-segment-distance.md)),
+leftover-map coordinate ticks ([ADR 0270](0270-leftover-map-coordinate-ticks.md)),
+leftover-map axis share on the graphic display
+([ADR 0269](0269-leftover-map-axis-share-plot.md)), leftover-map
+explained leftover share persistence
+([ADR 0266](0266-leftover-map-explained-share.md)), leftover-map
+unexplained leftover share persistence
+([ADR 0233](0233-leftover-map-unexplained-share.md)), leftover-map
+reconstruction persistence ([ADR 0201](0201-leftover-map-reconstruction.md)),
+and leftover-map axis share persistence ([ADR 0148](0148-leftover-map-axis-share.md)).
+
+## Context
+
+ADR 0233 already persists leftover-map unexplained leftover share
+`s = U² / R²` of raw residual after two-axis Gabriel reconstruction.
+ADR 0182 already persists unexplained leftover `U`. ADR 0273 already
+names persisted leftover-map explained leftover share `e` on the
+leftover-map graphic-display pair segment. The segment still has no
+unexplained leftover share label, so a buyer who reads `U²/R² 0.02`
+on the pair row cannot match that square share to the graphic pair.
+Hiding `s` on the segment lets leftover-map reconstruction `R̂`,
+leftover residual `R`, unexplained leftover `U`, or leftover-map
+explained leftover share `e` be read as the leftover the truncated map
+cannot reconstruct even after `e` is named on the segment. When `R`,
+`R̂`, `U`, `x`, `s`, and `e` are finite, `e + s + x = 1`; the graphic
+must name the same persisted `s` the pair row already shows.
+
+This increment names leftover-map graphic-display pair segments with
+persisted leftover-map unexplained leftover share. It does not add
+columns. It does not recompute `s` from `U` and `R` or from plotted
+coordinates. It does not persist leftover-map inner product, cosine, or
+length as separate columns. It does not land Post quality on the leftover
+criterion. Leftover-map distance stays two-axis Euclidean. Do not invent
+a leftover score. Do not invent a theta.
+
+The dashboard stack already used neighbouring leftover facts under
+other numbers. This protected increment uses **0274** so it does not
+collide with leftover-map explained leftover share on pair segments
+(0273), leftover-map reconstruction on pair segments (0272), leftover-map
+distance on pair segments (0271), leftover-map coordinate ticks (0270),
+leftover-map axis share on the graphic display (0269), leftover-map
+graphic display (0268), leftover-map coordinates (0267 / migration 0245),
+leftover-map explained leftover share persistence (0266 / migration 0244),
+leftover-map unexplained leftover share persistence (0233 / migration
+0233), leftover-map reconstruction persistence (0201 / migration 0206),
+leftover-map cross share (0185), leftover residual disclosure, leftover
+observed `Y` / expected `E`, leftover-map rank, two-axis leftover-map
+distance persistence, leftover coverage, leftover-map axis share
+persistence (0148), leftover interaction-map persistence, occupational
+construct catalog search (0265), or the dashboard stacks.
+
+## Decision
+
+On the leftover-map graphic display, caption each closest or farthest
+pair segment with the same persisted leftover-map unexplained leftover
+share formatter as the pair-row `U²/R²` badge. A missing or
+non-finite `s` omits that unexplained leftover share caption and keeps
+the connecting line and any leftover-map distance, reconstruction, or
+explained leftover share caption. Rank-0 origin cells still name
+`U²/R² 0.00` when that persisted share is finite. A finite share
+greater than 1 is shown, never clamped. Do not invent `s` from `U` and
+`R` or from plotted coordinates. Click a post marker to open that post.
+Criterion markers are not post buttons. The grouping comparison strip
+(ADR 0149) stays on its reduced leftover payload and does not gain these
+unexplained leftover share captions.
+
+Do not add SQL. Do not edit shipped migrations. Do not persist inner
+product, cosine, or length as separate columns. Do not invent a leftover
+score. Do not invent a theta.
+
+## Consequences
+
+After `make seed`, closest and farthest leftover pairs sit above the
+member list with the leftover-map graphic display of persisted `ξ`
+and `ζ`, leftover-map axes name persisted Gabriel inertia share when
+finite, leftover-map axis ticks name the same coordinates shown on
+the pair row, pair segments name persisted leftover-map distance `d`,
+persisted leftover-map reconstruction `R̂`, persisted leftover-map
+explained leftover share `e`, and persisted leftover-map unexplained
+leftover share `s`; click a post marker or a pair button opens that
+post. Hidden posts stay hidden. Rank-0 unused axes still plot at the
+origin, still name zero leftover-map axis share with a `0` tick, still
+name `d 0.00` when that distance is persisted, still name `R̂ 0.00`
+when that reconstruction is persisted, still name `R̂²/R² 0.00` when
+that explained leftover share is persisted, and still name `U²/R² 0.00`
+when that unexplained leftover share is persisted. When `R`, `R̂`, `U`,
+`x`, `s`, and `e` are all finite, `e + s + x = 1` remains the same
+identity already persisted by ADR 0233 and ADR 0266.
+
+## Related
+
+Independent of leftover interaction-map persistence, leftover-criterion
+evaluation landing, leftover residual disclosure, leftover observed
+`Y` / expected `E`, leftover-map complete-case coverage, leftover-map
+axis share persistence, leftover pairs on the grouping comparison
+strip, two-axis leftover-map distance persistence, leftover-map rank,
+leftover-map inner product, leftover-map cosine, leftover-map length,
+leftover-map reconstruction persistence, leftover-map unexplained
+leftover, leftover-map cross share, leftover-map unexplained leftover
+share persistence, leftover-map explained leftover share persistence,
+leftover-map coordinate persistence, leftover-map graphic display,
+leftover-map axis share on the graphic display, leftover-map coordinate
+ticks, leftover-map distance on pair segments, leftover-map reconstruction
+on pair segments, leftover-map explained leftover share on pair segments,
+and leftover-map cross share on pair segments.
+
+## References
+
+Gabriel, K. R. (1971). The biplot graphic display of matrices with
+application to principal component analysis. *Biometrika, 58*(3),
+453–467. https://doi.org/10.1093/biomet/58.3.453
+
+Jeon, M., Jin, I. H., Schweinberger, M., & Baugh, S. (2021). Mapping
+unobserved item–respondent interactions: A latent space item response
+model with interaction map. *Psychometrika, 86*(2), 378–403.
+https://doi.org/10.1007/s11336-021-09762-5
+(LSIRM interaction `−γ‖ξ_j − ζ_i‖` after main effects
+`α_j − β_i`; typically `p = 2` for the interaction map. Gabriel
+reconstruction of the leftover cell is the two-axis inner product
+`R̂ = ξ_{1:2} · ζ_{1:2}`. Unexplained leftover share is the square share
+`s = U² / R²` of the leftover the truncated map cannot reconstruct.)
diff --git a/docs/product-technical-gap-baseline.md b/docs/product-technical-gap-baseline.md
index ae32121c1..5dd2e2204 100644
--- a/docs/product-technical-gap-baseline.md
+++ b/docs/product-technical-gap-baseline.md
@@ -1,5 +1,38 @@
 # Product & Technical Gap Baseline
 
+> Exact-head loop overlay: 2026-08-29 20:20 KST. Protected `main` is
+> `fc13acaa20adca11968238e398d4aafcf62b6cee` (v2.23.0 leftover-map
+> explained leftover share, #775). Open ready PRs still lack independent
+> APPROVE. #782 leftover-map coordinates + graphic + axis share + ticks
+> + distance (v2.24.0–v2.28.0 / ADR 0267–0271) is on
+> `9bdd3e4d6e47a34ac22fca228b8d2a23d8cecca9` with auto-merge SQUASH
+> armed. Independent APPROVE is still required for protected main.
+> #802 leftover-map explained leftover share on pair segments (v2.30.0
+> / ADR 0273), replaying v2.29 reconstruction captions, is stacked on
+> leftover-coordinates at `79ec22f0a4b7236ab06500c7bf8f392da6a9419b`.
+> Leave #802 open for independent review. Do not squash-merge stacked
+> leftover PRs onto an unprotected leftover base. Auto-merge squash
+> remains armed on #782/#780/#774/#772/#771/#770. Drafts remain dirty
+> against `main`. #96 stays closed as a weaker duplicate of #91
+> (`state_reason` still 403). GitHub writes through `gh`/MCP succeed
+> (comment/create-PR/auto-merge). Copilot review is not independent
+> APPROVE. Do not self-approve.
+>
+> Next buyer increment on this cycle: leftover-map unexplained leftover
+> share `s` on graphic-display pair segments (ADR 0274 / v2.31.0)
+> delivered locally on
+> `feat/leftover-map-segment-unexplained-share-v2310`. Caption each
+> closest/farthest segment with persisted leftover-map unexplained
+> leftover share so the pair-row `U²/R²` badge matches the graphic.
+> UI-only; no new columns. Missing/non-finite `s` omits that unexplained
+> leftover share caption. A share greater than 1 is shown, never
+> clamped. Do not invent `s` from `U` and `R` or from plotted
+> coordinates. Do not invent leftover scores. Stack onto leftover branch
+> `feat/leftover-map-segment-explained-share-v2300`; leave the PR open
+> for independent review. Do not squash-merge onto the leftover base.
+> The following buyer increment is leftover-map cross share `x` on pair
+> segments so `e + s + x = 1` is graphic-auditable.
+
 > Exact-head loop overlay: 2026-08-29 20:00 KST. Protected `main` is
 > `fc13acaa20adca11968238e398d4aafcf62b6cee` (v2.23.0 leftover-map
 > explained leftover share, #775). Open ready PRs still lack independent
diff --git a/docs/storybook-inventory.md b/docs/storybook-inventory.md
index e26bd5c3b..13d926fd6 100644
--- a/docs/storybook-inventory.md
+++ b/docs/storybook-inventory.md
@@ -5,8 +5,8 @@ operator-facing control you can click before changing product CSS.
 
 | Story | Operator next action | Token / module |
 |---|---|---|
-| `Reports/LeftoverMapPlot` | Read the leftover-map graphic display of persisted `ξ` (posts) and `ζ` (criteria), match axis ticks to those coordinates, pair-segment `d` to leftover-map distance, pair-segment `R̂` to leftover-map reconstruction, and pair-segment `R̂²/R²` to leftover-map explained leftover share, then click a post marker to open that post. Leftover-map axes name persisted leftover-map axis share when finite. `ClosestAndFarthest`, `RankZeroOrigin`, `MissingCoordinates`, and `MissingAxisShare` cover two-pair maps, rank-0 origin with 0% share, a `0` tick, `d 0.00`, `R̂ 0.00`, and `R̂²/R² 0.00`, omitted plots, and missing share that keeps existing leftover-map axis text. The plot does not invent a leftover score. | `LeftoverMapPlot`, `leftoverMapPlotLayout`, `leftoverMapPlotAxisShare`, `--color-primary`, `--color-palette-blue-mid` |
-| `Reports/LeftoverPairList` | Read closest/farthest leftover pairs with named `R`, `Y`/`E`, rank, `U`, `s`, `e`, `x`, `R̂`, `ξ`/`ζ`, and `d`, then open that post. The leftover-map graphic display sits above the pair buttons when coordinates are finite, leftover-map axes name persisted leftover-map axis share, leftover-map axis ticks name persisted coordinates, pair segments name persisted leftover-map distance, pair segments name persisted leftover-map reconstruction, and pair segments name persisted leftover-map explained leftover share. | `LeftoverPairList`, `LeftoverMapPlot`, `ticket-list`, `post-badge` |
+| `Reports/LeftoverMapPlot` | Read the leftover-map graphic display of persisted `ξ` (posts) and `ζ` (criteria), match axis ticks to those coordinates, pair-segment `d` to leftover-map distance, pair-segment `R̂` to leftover-map reconstruction, pair-segment `R̂²/R²` to leftover-map explained leftover share, and pair-segment `U²/R²` to leftover-map unexplained leftover share, then click a post marker to open that post. Leftover-map axes name persisted leftover-map axis share when finite. `ClosestAndFarthest`, `RankZeroOrigin`, `MissingCoordinates`, and `MissingAxisShare` cover two-pair maps, rank-0 origin with 0% share, a `0` tick, `d 0.00`, `R̂ 0.00`, `R̂²/R² 0.00`, and `U²/R² 0.00`, omitted plots, and missing share that keeps existing leftover-map axis text. The plot does not invent a leftover score. | `LeftoverMapPlot`, `leftoverMapPlotLayout`, `leftoverMapPlotAxisShare`, `--color-primary`, `--color-palette-blue-mid` |
+| `Reports/LeftoverPairList` | Read closest/farthest leftover pairs with named `R`, `Y`/`E`, rank, `U`, `s`, `e`, `x`, `R̂`, `ξ`/`ζ`, and `d`, then open that post. The leftover-map graphic display sits above the pair buttons when coordinates are finite, leftover-map axes name persisted leftover-map axis share, leftover-map axis ticks name persisted coordinates, pair segments name persisted leftover-map distance, pair segments name persisted leftover-map reconstruction, pair segments name persisted leftover-map explained leftover share, and pair segments name persisted leftover-map unexplained leftover share. | `LeftoverPairList`, `LeftoverMapPlot`, `ticket-list`, `post-badge` |
 | `Workspace/OperationsDashboard` | Compare Event and post counts, inspect external-information coverage, then open the cited source behind a claim, handover, or repeat-issue fact. `EvidenceReady`, `NarrowViewport`, `AnalysisPendingAndMissingEvidence`, `AnalysisFailed`, and `LoadError` cover populated, mobile, unavailable-evidence, analysis-pending, retryable failure, and transport-error states. | `--color-dashboard-*`, `OperationsDashboard` |
 | `Post/SimilarVocPanel` | Compare ontology/semantic similar VOC and prior action evidence, then open the source; unavailable states show no fabricated TEPP theta or weight. | `SimilarVocPanel.css`, `SimilarVocPanel` |
 | `Post/Recorded perspectives` | Read the imported primary and every evidence-connected additional Voice with its recorded truth state instead of flattening them into one compound category. `CombinedEvidence`, `RejectedEvidence`, and `NarrowViewport` cover desktop, rejected-evidence, and narrow layouts. | `VoicePerspectiveList`, `ticket-list`, `post-meta` |
diff --git a/frontend/package.json b/frontend/package.json
index 8a01b19f8..c0fbd16f6 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,7 +1,7 @@
 {
   "name": "frontend",
   "private": true,
-  "version": "2.30.0",
+  "version": "2.31.0",
   "type": "module",
   "scripts": {
     "dev": "vite",
diff --git a/frontend/src/components/LeftoverMapPlot.stories.tsx b/frontend/src/components/LeftoverMapPlot.stories.tsx
index aad15812e..91ccf8bc7 100644
--- a/frontend/src/components/LeftoverMapPlot.stories.tsx
+++ b/frontend/src/components/LeftoverMapPlot.stories.tsx
@@ -82,6 +82,7 @@ export const RankZeroOrigin: Story = {
         leftover_map_rank: 0,
         leftover_map_reconstruction: 0,
         leftover_map_explained_share: 0,
+        leftover_map_unexplained_share: 0,
         leftover_map_person_axis_1: 0,
         leftover_map_person_axis_2: 0,
         leftover_map_item_axis_1: 0,
diff --git a/frontend/src/components/LeftoverMapPlot.test.tsx b/frontend/src/components/LeftoverMapPlot.test.tsx
index 8b2067652..156942cb3 100644
--- a/frontend/src/components/LeftoverMapPlot.test.tsx
+++ b/frontend/src/components/LeftoverMapPlot.test.tsx
@@ -14,6 +14,7 @@ const PAIRS: LeftoverPair[] = [
     leftover_residual: 0.4,
     leftover_map_reconstruction: 0.248,
     leftover_map_explained_share: 0.76,
+    leftover_map_unexplained_share: 0.02,
     leftover_map_person_axis_1: 0.5,
     leftover_map_person_axis_2: 0.1,
     leftover_map_item_axis_1: 0.5,
@@ -28,6 +29,7 @@ const PAIRS: LeftoverPair[] = [
     leftover_residual: -1.1,
     leftover_map_reconstruction: -0.95,
     leftover_map_explained_share: 0.6,
+    leftover_map_unexplained_share: 0.05,
     leftover_map_person_axis_1: 0.9,
     leftover_map_person_axis_2: 0.8,
     leftover_map_item_axis_1: -0.7,
@@ -49,7 +51,7 @@ describe("LeftoverMapPlot", () => {
     expect(screen.getByLabelText("Leftover-map graphic display")).toBeInTheDocument();
     expect(
       screen.getByText(
-        "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.",
+        "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.",
       ),
     ).toBeInTheDocument();
     expect(screen.getByText("Post ξ")).toBeInTheDocument();
@@ -65,6 +67,8 @@ describe("LeftoverMapPlot", () => {
     expect(screen.getByLabelText("leftover-map reconstruction R̂ −0.95")).toBeInTheDocument();
     expect(screen.getByLabelText("leftover-map explained leftover share R̂²/R² 0.76")).toBeInTheDocument();
     expect(screen.getByLabelText("leftover-map explained leftover share R̂²/R² 0.60")).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map unexplained leftover share U²/R² 0.02")).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map unexplained leftover share U²/R² 0.05")).toBeInTheDocument();
 
     const postMarker = screen.getByRole("button", {
       name: "Open leftover-map post Public post at ξ (+0.50, +0.10)",
@@ -113,6 +117,7 @@ describe("LeftoverMapPlot", () => {
             leftover_map_rank: 0,
             leftover_map_reconstruction: 0,
             leftover_map_explained_share: 0,
+            leftover_map_unexplained_share: 0,
             leftover_map_person_axis_1: 0,
             leftover_map_person_axis_2: 0,
             leftover_map_item_axis_1: 0,
@@ -137,6 +142,7 @@ describe("LeftoverMapPlot", () => {
     expect(screen.getByLabelText("leftover-map distance d 0.00")).toBeInTheDocument();
     expect(screen.getByLabelText("leftover-map reconstruction R̂ 0.00")).toBeInTheDocument();
     expect(screen.getByLabelText("leftover-map explained leftover share R̂²/R² 0.00")).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map unexplained leftover share U²/R² 0.00")).toBeInTheDocument();
   });
 
   it("captions leftover-map axes with persisted leftover-map axis share", () => {
@@ -250,4 +256,33 @@ describe("LeftoverMapPlot", () => {
     expect(screen.getByLabelText("leftover-map reconstruction R̂ +0.25")).toBeInTheDocument();
     expect(screen.getByLabelText("leftover-map distance d 0.12")).toBeInTheDocument();
   });
+
+  it("omits leftover-map unexplained leftover share on a pair segment when s is missing", () => {
+    render(
+      <LeftoverMapPlot
+        pairs={[
+          {
+            pair_kind: "closest",
+            post_id: "post-demo-public",
+            post_title: "Public post",
+            criterion_code: "sales_lead_quality",
+            leftover_distance: 0.12,
+            leftover_residual: 0.4,
+            leftover_map_reconstruction: 0.248,
+            leftover_map_explained_share: 0.76,
+            leftover_map_unexplained_share: Number.NaN,
+            leftover_map_person_axis_1: 0.5,
+            leftover_map_person_axis_2: 0.1,
+            leftover_map_item_axis_1: 0.5,
+            leftover_map_item_axis_2: -0.02,
+          },
+        ]}
+        criterionLabel={criterionLabel}
+        onSelectPost={vi.fn()}
+      />,
+    );
+    expect(screen.queryByLabelText(/leftover-map unexplained leftover share/)).not.toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map explained leftover share R̂²/R² 0.76")).toBeInTheDocument();
+    expect(screen.getByLabelText("leftover-map reconstruction R̂ +0.25")).toBeInTheDocument();
+  });
 });
diff --git a/frontend/src/components/LeftoverMapPlot.tsx b/frontend/src/components/LeftoverMapPlot.tsx
index 29ffed490..45919e4c6 100644
--- a/frontend/src/components/LeftoverMapPlot.tsx
+++ b/frontend/src/components/LeftoverMapPlot.tsx
@@ -14,6 +14,7 @@ import {
   LEFTOVER_MAP_PLOT_SEGMENT_DISTANCE,
   LEFTOVER_MAP_PLOT_SEGMENT_EXPLAINED_SHARE,
   LEFTOVER_MAP_PLOT_SEGMENT_RECONSTRUCTION,
+  LEFTOVER_MAP_PLOT_SEGMENT_UNEXPLAINED_SHARE,
   LEFTOVER_MAP_PLOT_TICK,
 } from "../leftoverMapPlotLayout";
 import "./LeftoverMapPlot.css";
@@ -50,12 +51,14 @@ function leftoverMapPlotAxisText(
  * Gabriel inertia share when finite, including rank-0 zero-share axes.
  * Axis ticks name persisted leftover-map coordinates so ξ / ζ on the
  * pair row match the plot. Pair segments name persisted leftover-map
- * distance ``d``, leftover-map reconstruction ``R̂``, and leftover-map
- * explained leftover share ``e`` so the pair-row badges match the graphic.
+ * distance ``d``, leftover-map reconstruction ``R̂``, leftover-map
+ * explained leftover share ``e``, and leftover-map unexplained leftover
+ * share ``s`` so the pair-row badges match the graphic.
  * Omit that distance caption when ``d`` is missing or non-finite. Omit
  * that reconstruction caption when ``R̂`` is missing or non-finite. Omit
  * that explained leftover share caption when ``e`` is missing or
- * non-finite. Omit that axis badge when share is missing or non-finite
+ * non-finite. Omit that unexplained leftover share caption when ``s`` is
+ * missing or non-finite. Omit that axis badge when share is missing or non-finite
  * and keep the existing leftover-map axis text. Omit the plot when no
  * pair has four finite leftover-map coordinates. Never invent a leftover
  * score.
@@ -183,6 +186,19 @@ export function LeftoverMapPlot({
                   {segment.explainedShareLabel}
                 </text>
               ) : null}
+              {segment.unexplainedShareLabel !== null ? (
+                <text
+                  className="leftover-map-plot-segment-label leftover-map-plot-segment-unexplained-share"
+                  x={segment.unexplainedShareX}
+                  y={segment.unexplainedShareY}
+                  textAnchor="middle"
+                  aria-label={tf(LEFTOVER_MAP_PLOT_SEGMENT_UNEXPLAINED_SHARE, {
+                    label: segment.unexplainedShareLabel,
+                  })}
+                >
+                  {segment.unexplainedShareLabel}
+                </text>
+              ) : null}
             </g>
           ))}
           {layout.items.map((marker) => (
diff --git a/frontend/src/components/LeftoverPairList.tsx b/frontend/src/components/LeftoverPairList.tsx
index 75e500821..b0fd2c910 100644
--- a/frontend/src/components/LeftoverPairList.tsx
+++ b/frontend/src/components/LeftoverPairList.tsx
@@ -63,7 +63,9 @@ export type LeftoverPairListProps = {
  * the plot. ADR 0271 names persisted leftover-map distance ``d`` on those
  * pair segments. ADR 0272 names persisted leftover-map reconstruction
  * ``R̂`` on those pair segments. ADR 0273 names persisted leftover-map
- * explained leftover share ``e`` on those pair segments. Every badge still
+ * explained leftover share ``e`` on those pair segments. ADR 0274 names
+ * persisted leftover-map unexplained leftover share ``s`` on those pair
+ * segments. Every badge still
  * renders together before opening the named post.
  */
 export function LeftoverPairList({
diff --git a/frontend/src/i18n.test.ts b/frontend/src/i18n.test.ts
index 6feba1e48..e9b579126 100644
--- a/frontend/src/i18n.test.ts
+++ b/frontend/src/i18n.test.ts
@@ -69,7 +69,8 @@ describe("i18n", () => {
     "leftover-map distance {label}",
     "leftover-map reconstruction {label}",
     "leftover-map explained leftover share {label}",
-    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.",
+    "leftover-map unexplained leftover share {label}",
+    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.",
     "Open leftover-map post {title} at ξ {person}",
     "Read observed Y {observed} and expected E {expected} after IRT main effects, then open this post.",
     "Leftover map has no leftover structure after IRT main effects. Open this post.",
@@ -333,22 +334,22 @@ describe("i18n", () => {
   it.each([
     [
       "ko",
-      "IRT 주효과 이후 잔여 지도입니다. 축 눈금은 저장된 잔여 지도 좌표입니다. 쌍 선분은 잔여 지도 거리 d, 잔여 지도 재구성 R̂, 잔여 지도 설명 잔여 점유율 e입니다. 글 표식을 눌러 그 글을 여세요. 이 그림은 잔여 점수를 만들어내지 않습니다.",
+      "IRT 주효과 이후 잔여 지도입니다. 축 눈금은 저장된 잔여 지도 좌표입니다. 쌍 선분은 잔여 지도 거리 d, 잔여 지도 재구성 R̂, 잔여 지도 설명 잔여 점유율 e, 잔여 지도 미설명 잔여 점유율 s입니다. 글 표식을 눌러 그 글을 여세요. 이 그림은 잔여 점수를 만들어내지 않습니다.",
     ],
-    ["zh", "IRT 主效应后的残差图。轴刻度标出已保存的残差图坐标。配对线段标出残差图距离 d、残差图重建 R̂ 与残差图已解释残差份额 e。点击帖子标记打开该帖子。此图不会虚构残差分数。"],
+    ["zh", "IRT 主效应后的残差图。轴刻度标出已保存的残差图坐标。配对线段标出残差图距离 d、残差图重建 R̂、残差图已解释残差份额 e 与残差图未解释残差份额 s。点击帖子标记打开该帖子。此图不会虚构残差分数。"],
     [
       "ja",
-      "IRT主効果後の残差マップです。軸目盛は保存済みの残差マップ座標です。ペア線分は残差マップ距離 d、残差マップ再構成 R̂、残差マップ説明済み残差割合 e です。投稿マーカーをクリックしてその投稿を開いてください。この図は残差スコアを作りません。",
+      "IRT主効果後の残差マップです。軸目盛は保存済みの残差マップ座標です。ペア線分は残差マップ距離 d、残差マップ再構成 R̂、残差マップ説明済み残差割合 e、残差マップ未説明残差割合 s です。投稿マーカーをクリックしてその投稿を開いてください。この図は残差スコアを作りません。",
     ],
     [
       "vi",
-      "Bản đồ phần dư sau hiệu ứng chính IRT. Vạch trục ghi tọa độ bản đồ phần dư đã lưu. Đoạn cặp ghi khoảng cách bản đồ phần dư d, tái dựng bản đồ phần dư R̂ và phần dư giải thích e. Nhấn dấu bài viết để mở bài đó. Hình này không tạo ra điểm phần dư.",
+      "Bản đồ phần dư sau hiệu ứng chính IRT. Vạch trục ghi tọa độ bản đồ phần dư đã lưu. Đoạn cặp ghi khoảng cách bản đồ phần dư d, tái dựng bản đồ phần dư R̂, phần dư giải thích e và phần dư chưa giải thích s. Nhấn dấu bài viết để mở bài đó. Hình này không tạo ra điểm phần dư.",
     ],
   ] as const)("formats leftover-map graphic display caption in %s", (locale, expected) => {
     setLocale(locale);
     expect(
       t(
-        "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.",
+        "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.",
       ),
     ).toBe(expected);
   });
@@ -395,6 +396,18 @@ describe("i18n", () => {
     );
   });
 
+  it.each([
+    ["ko", "잔여 지도 미설명 잔여 점유율 U²/R² 0.02"],
+    ["zh", "残差图未解释残差份额 U²/R² 0.02"],
+    ["ja", "残差マップ未説明残差割合 U²/R² 0.02"],
+    ["vi", "phần dư chưa giải thích bản đồ phần dư U²/R² 0.02"],
+  ] as const)("formats leftover-map segment unexplained leftover share in %s", (locale, expected) => {
+    setLocale(locale);
+    expect(tf("leftover-map unexplained leftover share {label}", { label: "U²/R² 0.02" })).toBe(
+      expected,
+    );
+  });
+
   it.each([
     ["ko", "잔여 지도 축 1 (82%)"],
     ["zh", "残差图轴 1 (82%)"],
diff --git a/frontend/src/i18n.ts b/frontend/src/i18n.ts
index 52f64363c..5c8f0aa9c 100644
--- a/frontend/src/i18n.ts
+++ b/frontend/src/i18n.ts
@@ -594,8 +594,9 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "leftover-map distance {label}": "잔여 지도 거리 {label}",
     "leftover-map reconstruction {label}": "잔여 지도 재구성 {label}",
     "leftover-map explained leftover share {label}": "잔여 지도 설명 잔여 점유율 {label}",
-    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.":
-      "IRT 주효과 이후 잔여 지도입니다. 축 눈금은 저장된 잔여 지도 좌표입니다. 쌍 선분은 잔여 지도 거리 d, 잔여 지도 재구성 R̂, 잔여 지도 설명 잔여 점유율 e입니다. 글 표식을 눌러 그 글을 여세요. 이 그림은 잔여 점수를 만들어내지 않습니다.",
+    "leftover-map unexplained leftover share {label}": "잔여 지도 미설명 잔여 점유율 {label}",
+    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.":
+      "IRT 주효과 이후 잔여 지도입니다. 축 눈금은 저장된 잔여 지도 좌표입니다. 쌍 선분은 잔여 지도 거리 d, 잔여 지도 재구성 R̂, 잔여 지도 설명 잔여 점유율 e, 잔여 지도 미설명 잔여 점유율 s입니다. 글 표식을 눌러 그 글을 여세요. 이 그림은 잔여 점수를 만들어내지 않습니다.",
     "Open leftover-map post {title} at ξ {person}":
       "잔여 지도 글 {title} 열기 (ξ {person})",
     "Read observed Y {observed} and expected E {expected} after IRT main effects, then open this post.":
@@ -1176,8 +1177,9 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "leftover-map distance {label}": "残差图距离 {label}",
     "leftover-map reconstruction {label}": "残差图重建 {label}",
     "leftover-map explained leftover share {label}": "残差图已解释残差份额 {label}",
-    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.":
-      "IRT 主效应后的残差图。轴刻度标出已保存的残差图坐标。配对线段标出残差图距离 d、残差图重建 R̂ 与残差图已解释残差份额 e。点击帖子标记打开该帖子。此图不会虚构残差分数。",
+    "leftover-map unexplained leftover share {label}": "残差图未解释残差份额 {label}",
+    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.":
+      "IRT 主效应后的残差图。轴刻度标出已保存的残差图坐标。配对线段标出残差图距离 d、残差图重建 R̂、残差图已解释残差份额 e 与残差图未解释残差份额 s。点击帖子标记打开该帖子。此图不会虚构残差分数。",
     "Open leftover-map post {title} at ξ {person}":
       "打开残差图帖子 {title}（ξ {person}）",
     "Read observed Y {observed} and expected E {expected} after IRT main effects, then open this post.":
@@ -1762,8 +1764,9 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "leftover-map distance {label}": "残差マップ距離 {label}",
     "leftover-map reconstruction {label}": "残差マップ再構成 {label}",
     "leftover-map explained leftover share {label}": "残差マップ説明済み残差割合 {label}",
-    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.":
-      "IRT主効果後の残差マップです。軸目盛は保存済みの残差マップ座標です。ペア線分は残差マップ距離 d、残差マップ再構成 R̂、残差マップ説明済み残差割合 e です。投稿マーカーをクリックしてその投稿を開いてください。この図は残差スコアを作りません。",
+    "leftover-map unexplained leftover share {label}": "残差マップ未説明残差割合 {label}",
+    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.":
+      "IRT主効果後の残差マップです。軸目盛は保存済みの残差マップ座標です。ペア線分は残差マップ距離 d、残差マップ再構成 R̂、残差マップ説明済み残差割合 e、残差マップ未説明残差割合 s です。投稿マーカーをクリックしてその投稿を開いてください。この図は残差スコアを作りません。",
     "Open leftover-map post {title} at ξ {person}":
       "残差マップの投稿 {title} を開く（ξ {person}）",
     "Read observed Y {observed} and expected E {expected} after IRT main effects, then open this post.":
@@ -2348,8 +2351,9 @@ const TRANSLATIONS: Partial<Record<Locale, Record<string, string>>> = {
     "leftover-map distance {label}": "khoảng cách bản đồ phần dư {label}",
     "leftover-map reconstruction {label}": "tái dựng bản đồ phần dư {label}",
     "leftover-map explained leftover share {label}": "phần dư giải thích bản đồ phần dư {label}",
-    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.":
-      "Bản đồ phần dư sau hiệu ứng chính IRT. Vạch trục ghi tọa độ bản đồ phần dư đã lưu. Đoạn cặp ghi khoảng cách bản đồ phần dư d, tái dựng bản đồ phần dư R̂ và phần dư giải thích e. Nhấn dấu bài viết để mở bài đó. Hình này không tạo ra điểm phần dư.",
+    "leftover-map unexplained leftover share {label}": "phần dư chưa giải thích bản đồ phần dư {label}",
+    "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.":
+      "Bản đồ phần dư sau hiệu ứng chính IRT. Vạch trục ghi tọa độ bản đồ phần dư đã lưu. Đoạn cặp ghi khoảng cách bản đồ phần dư d, tái dựng bản đồ phần dư R̂, phần dư giải thích e và phần dư chưa giải thích s. Nhấn dấu bài viết để mở bài đó. Hình này không tạo ra điểm phần dư.",
     "Open leftover-map post {title} at ξ {person}":
       "Mở bài viết bản đồ phần dư {title} tại ξ {person}",
     "Read observed Y {observed} and expected E {expected} after IRT main effects, then open this post.":
diff --git a/frontend/src/leftoverMapPlotLayout.test.ts b/frontend/src/leftoverMapPlotLayout.test.ts
index ac6fe5ed8..52d1c2317 100644
--- a/frontend/src/leftoverMapPlotLayout.test.ts
+++ b/frontend/src/leftoverMapPlotLayout.test.ts
@@ -25,6 +25,7 @@ function pair(
     leftover_distance: 0.12,
     leftover_map_reconstruction: 0.248,
     leftover_map_explained_share: 0.76,
+    leftover_map_unexplained_share: 0.02,
     ...overrides,
   };
 }
@@ -434,6 +435,98 @@ describe("layoutLeftoverMapPlot", () => {
     expect(layout?.segments[0]?.reconstructionLabel).toBe("R\u0302 0.00");
     expect(layout?.segments[0]?.distanceLabel).toBe("d 0.00");
   });
+
+  it("names persisted leftover-map unexplained leftover share on pair segments without inventing a leftover score", () => {
+    const layout = layoutLeftoverMapPlot(
+      [
+        pair(),
+        pair({
+          pair_kind: "farthest",
+          post_id: "post-demo-spec",
+          criterion_code: "negative_sentiment",
+          leftover_map_person_axis_1: 0.9,
+          leftover_map_person_axis_2: 0.8,
+          leftover_map_item_axis_1: -0.7,
+          leftover_map_item_axis_2: -0.4,
+          leftover_distance: 1.84,
+          leftover_map_reconstruction: -0.95,
+          leftover_map_explained_share: 0.6,
+          leftover_map_unexplained_share: 0.05,
+        }),
+      ],
+      criterionLabel,
+    );
+    expect(layout?.segments.map((segment) => segment.unexplainedShareLabel)).toEqual([
+      "U\u00b2/R\u00b2 0.02",
+      "U\u00b2/R\u00b2 0.05",
+    ]);
+    expect(layout?.segments[0]?.unexplainedShareX).toBeCloseTo(layout?.segments[0]?.labelX ?? 0, 5);
+    expect(layout?.segments[0]?.unexplainedShareY).toBeGreaterThan(
+      layout?.segments[0]?.explainedShareY ?? 0,
+    );
+  });
+
+  it("omits a leftover-map unexplained leftover share caption when s is missing or non-finite", () => {
+    const layout = layoutLeftoverMapPlot(
+      [
+        pair({ leftover_map_unexplained_share: null }),
+        pair({
+          pair_kind: "farthest",
+          leftover_map_unexplained_share: Number.NaN,
+          leftover_map_item_axis_1: -0.7,
+          leftover_map_item_axis_2: -0.4,
+          criterion_code: "negative_sentiment",
+        }),
+      ],
+      criterionLabel,
+    );
+    expect(layout?.segments.map((segment) => segment.unexplainedShareLabel)).toEqual([null, null]);
+    expect(layout?.segments.map((segment) => segment.explainedShareLabel)).toEqual([
+      "R\u0302\u00b2/R\u00b2 0.76",
+      "R\u0302\u00b2/R\u00b2 0.76",
+    ]);
+  });
+
+  it("does not invent leftover-map unexplained leftover share from unexplained leftover or residual", () => {
+    const layout = layoutLeftoverMapPlot(
+      [
+        pair({
+          leftover_map_person_axis_1: 1,
+          leftover_map_person_axis_2: 0,
+          leftover_map_item_axis_1: 1,
+          leftover_map_item_axis_2: 0,
+          leftover_map_reconstruction: 1,
+          leftover_map_explained_share: 0.76,
+          leftover_map_unexplained_share: 0.02,
+        }),
+      ],
+      criterionLabel,
+    );
+    expect(layout?.segments[0]?.unexplainedShareLabel).toBe("U\u00b2/R\u00b2 0.02");
+    expect(layout?.segments[0]?.unexplainedShareLabel).not.toBe("U\u00b2/R\u00b2 1.00");
+  });
+
+  it("names rank-0 origin unexplained leftover share s 0.00 when that persisted value is finite", () => {
+    const layout = layoutLeftoverMapPlot(
+      [
+        pair({
+          leftover_map_person_axis_1: 0,
+          leftover_map_person_axis_2: 0,
+          leftover_map_item_axis_1: 0,
+          leftover_map_item_axis_2: 0,
+          leftover_distance: 0,
+          leftover_map_reconstruction: 0,
+          leftover_map_explained_share: 0,
+          leftover_map_unexplained_share: 0,
+        }),
+      ],
+      criterionLabel,
+    );
+    expect(layout?.segments[0]?.unexplainedShareLabel).toBe("U\u00b2/R\u00b2 0.00");
+    expect(layout?.segments[0]?.explainedShareLabel).toBe("R\u0302\u00b2/R\u00b2 0.00");
+    expect(layout?.segments[0]?.reconstructionLabel).toBe("R\u0302 0.00");
+    expect(layout?.segments[0]?.distanceLabel).toBe("d 0.00");
+  });
 });
 
 describe("formatLeftoverMapDistance", () => {
diff --git a/frontend/src/leftoverMapPlotLayout.ts b/frontend/src/leftoverMapPlotLayout.ts
index 7cc26c807..8ab992677 100644
--- a/frontend/src/leftoverMapPlotLayout.ts
+++ b/frontend/src/leftoverMapPlotLayout.ts
@@ -2,18 +2,20 @@
  *  Leftover-map axis share captions axes 1 and 2 when finite (ADR 0269).
  *  Axis ticks name persisted leftover-map coordinates (ADR 0270).
  *  Pair segments name persisted leftover-map distance ``d`` (ADR 0271),
- *  persisted leftover-map reconstruction ``R̂`` (ADR 0272), and persisted
- *  leftover-map explained leftover share ``e`` (ADR 0273).
+ *  persisted leftover-map reconstruction ``R̂`` (ADR 0272), persisted
+ *  leftover-map explained leftover share ``e`` (ADR 0273), and persisted
+ *  leftover-map unexplained leftover share ``s`` (ADR 0274).
  */
 
 import { formatLeftoverMapCoordinatePair } from "./leftoverMapCoordinates";
 import { formatLeftoverMapExplainedShare } from "./leftoverMapExplainedShare";
 import { formatLeftoverMapReconstruction } from "./leftoverMapReconstruction";
+import { formatLeftoverMapUnexplainedShare } from "./leftoverMapUnexplainedShare";
 import { formatSignedLeftoverValue } from "./leftoverMapUnexplained";
 import type { LeftoverPair } from "./api";
 
 export const LEFTOVER_MAP_PLOT_CAPTION =
-  "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, and leftover-map explained leftover share e. Click a post marker to open that post. The plot does not invent a leftover score.";
+  "Leftover map after IRT main effects. Axis ticks name persisted leftover-map coordinates. Pair segments name leftover-map distance d, leftover-map reconstruction R̂, leftover-map explained leftover share e, and leftover-map unexplained leftover share s. Click a post marker to open that post. The plot does not invent a leftover score.";
 
 export const LEFTOVER_MAP_PLOT_POST_ACTION =
   "Open leftover-map post {title} at ξ {person}";
@@ -30,6 +32,9 @@ export const LEFTOVER_MAP_PLOT_SEGMENT_RECONSTRUCTION =
 export const LEFTOVER_MAP_PLOT_SEGMENT_EXPLAINED_SHARE =
   "leftover-map explained leftover share {label}";
 
+export const LEFTOVER_MAP_PLOT_SEGMENT_UNEXPLAINED_SHARE =
+  "leftover-map unexplained leftover share {label}";
+
 export const PLOT_WIDTH = 480;
 export const PLOT_HEIGHT = 320;
 export const PLOT_PADDING = 40;
@@ -47,6 +52,7 @@ export type LeftoverMapPlottablePair = {
   leftover_distance?: number | null;
   leftover_map_reconstruction?: number | null;
   leftover_map_explained_share?: number | null;
+  leftover_map_unexplained_share?: number | null;
   leftover_map_person_axis_1?: number | null;
   leftover_map_person_axis_2?: number | null;
   leftover_map_item_axis_1?: number | null;
@@ -74,12 +80,15 @@ export type LeftoverMapPlotSegment = {
   distanceLabel: string | null;
   reconstructionLabel: string | null;
   explainedShareLabel: string | null;
+  unexplainedShareLabel: string | null;
   labelX: number;
   labelY: number;
   reconstructionX: number;
   reconstructionY: number;
   explainedShareX: number;
   explainedShareY: number;
+  unexplainedShareX: number;
+  unexplainedShareY: number;
 };
 
 export type LeftoverMapPlotTick = {
@@ -303,6 +312,9 @@ export function layoutLeftoverMapPlot(
     const explainedShareLabel = formatLeftoverMapExplainedShare(
       pair.leftover_map_explained_share,
     );
+    const unexplainedShareLabel = formatLeftoverMapUnexplainedShare(
+      pair.leftover_map_unexplained_share,
+    );
     const labelPosition = leftoverMapSegmentLabelPosition(
       personPos.x,
       personPos.y,
@@ -317,6 +329,12 @@ export function layoutLeftoverMapPlot(
       labelPosition.labelY,
       (distanceLabel !== null ? 1 : 0) + (reconstructionLabel !== null ? 1 : 0),
     );
+    const unexplainedShareY = leftoverMapStackedCaptionY(
+      labelPosition.labelY,
+      (distanceLabel !== null ? 1 : 0) +
+        (reconstructionLabel !== null ? 1 : 0) +
+        (explainedShareLabel !== null ? 1 : 0),
+    );
     segments.push({
       pairKind: pair.pair_kind === "farthest" ? "farthest" : "closest",
       postId: pair.post_id,
@@ -328,10 +346,13 @@ export function layoutLeftoverMapPlot(
       distanceLabel,
       reconstructionLabel,
       explainedShareLabel,
+      unexplainedShareLabel,
       reconstructionX: labelPosition.labelX,
       reconstructionY,
       explainedShareX: labelPosition.labelX,
       explainedShareY,
+      unexplainedShareX: labelPosition.labelX,
+      unexplainedShareY,
       ...labelPosition,
     });
   }
diff --git a/pyproject.toml b/pyproject.toml
index 839a61c8d..98f938768 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "lineageweave"
-version = "2.30.0"
+version = "2.31.0"
 description = "Reconstructs git-branch-style lineage DAGs from scattered short records using multi-channel score fusion and LLM adjudication."
 readme = "README.md"
 license = { text = "MIT" }
diff --git a/uv.lock b/uv.lock
index b21381b50..3b22a4111 100644
--- a/uv.lock
+++ b/uv.lock
@@ -685,7 +685,7 @@ wheels = [
 
 [[package]]
 name = "lineageweave"
-version = "2.30.0"
+version = "2.31.0"
 source = { editable = "." }
 dependencies = [
     { name = "certifi" },