diff --git a/plugin/core/constants.py b/plugin/core/constants.py
index 7e89d2e7d..398fcc528 100644
--- a/plugin/core/constants.py
+++ b/plugin/core/constants.py
@@ -287,6 +287,8 @@ class ChangeEventAction(IntEnum):
     "source.cs": LanguageKind.CSharp,
     "source.dosbatch": LanguageKind.WindowsBat,
     "source.fixedform-fortran": "fortran",  # https://packagecontrol.io/packages/Fortran
+    "source.gjs": "glimmer-js",
+    "source.gts": "glimmer-ts",
     "source.js": LanguageKind.JavaScript,
     "source.js.react": LanguageKind.JavaScriptReact,  # https://github.com/Thom1729/Sublime-JS-Custom
     "source.json-tmlanguage": "jsonc",  # https://github.com/SublimeText/PackageDev