There’s indeed a new security feature which might be causing that. It’s not yet documented, will be documenetd soon. Meanwhile you can find the draft documentation which is probably “approximately correct” here:
master ← assisted-by-ai:claude/build-fm-shim-backend-SMfJx
opened 10:19AM - 08 Apr 26 UTC
## Summary
This change adds documentation for the File Manager D-Bus shim, a … new security feature that intercepts and controls D-Bus access to the file manager.
## Changes
- Added comprehensive documentation section explaining the File Manager D-Bus shim functionality
- Documented the two-component architecture:
- C backend that intercepts `org.freedesktop.FileManager1` D-Bus method calls with hardening flags (`_FORTIFY_SOURCE=3`, PIE, RELRO, CFI)
- Python/PyQt5 frontend that validates URIs, resolves symlinks, and presents user confirmation dialogs
- Documented security features including URI validation (local `file://` only), rejection of Unicode/control characters, path existence verification, and symlink resolution
- Listed relevant source files and configuration locations for reference
## Details
The documentation explains how the shim prevents applications from silently opening directories via D-Bus by requiring explicit user confirmation. It addresses PCManFM-Qt D-Bus handling issues while providing an additional control layer for users. The backend runs as a systemd user service that automatically starts on login.
https://claude.ai/code/session_01RHBTARXyvjzrgxyCX6ntnA