An AppImage runs the program from a mount that goes away with the image it came from, so a host held open past an update kept running the old mount and never noticed the replaced image. The host now reads APPIMAGE (added to its environment allow-list only when it names an absolute file; it is a path the host reads about itself and never tells an agent, so I-2 holds), runs and restarts from that file, and tells a replaced program by its file's inode, size and last write. Test: a_replaced_appimage_restarts_the_books (the programs run from one file while APPIMAGE names another, as in a mount). Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp