I'm considering this proposal from the perspective of the WebExtensions platform. The ability to have an iframe that persists across navigations could be a useful primitive in order for WebExtensions to display UI that persists across navigations.
We've discussed similar ideas in the past, most recently at our 2026 Face to Face meeting. See the discussion around how DevTools displays content on top of everything in https://github.com/w3c/webextensions/blob/main/_minutes/2026-04-07-london-f2f.md#click-jacking-protection:~:text=something%20similar%20to-,DevTools%27%20approach,-to%20displaying%20content.
At this point it's not clear to me whether this should be an explicit use case for this proposal or if it should just be a consideration during design/implementation. The intent with the latter is that WebExtensions would be able to leverage the persistent iframes infrastructure rather than potentially inventing a parallel concept.
I'm considering this proposal from the perspective of the WebExtensions platform. The ability to have an iframe that persists across navigations could be a useful primitive in order for WebExtensions to display UI that persists across navigations.
We've discussed similar ideas in the past, most recently at our 2026 Face to Face meeting. See the discussion around how DevTools displays content on top of everything in https://github.com/w3c/webextensions/blob/main/_minutes/2026-04-07-london-f2f.md#click-jacking-protection:~:text=something%20similar%20to-,DevTools%27%20approach,-to%20displaying%20content.
At this point it's not clear to me whether this should be an explicit use case for this proposal or if it should just be a consideration during design/implementation. The intent with the latter is that WebExtensions would be able to leverage the persistent iframes infrastructure rather than potentially inventing a parallel concept.