Your system information

It's a Steam Deck.

• Steam client version (build number or date): 1748033199
• Distribution (e.g. Ubuntu): SteamOS
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes
• Steam Logs: steam-logs.tar.gz

Please describe your issue in as much detail as possible:

It used to be possible to run steam://resetcollections to, well, reset game collections. This was exceptionally useful in cases where the Steam library was modified by a third-party tool while Steam itself was not running.
Now, with the command seemingly removed, modifying the library like this will result in half-broken collections and no way to fix them properly.

Steps for reproducing this issue:

1. Use a tool like my own Steam Librarian or Steam ROM Manager to modify your library and make the tool sort newly added games into either new or already existing collections
2. Restart Steam
3. Check out your broken collections