Currently univention-run-diagnostic-checks always prompts for admin credentials, even for --list. This is a bit braindead.
What do you suggest instead? The credentials are required because listing the plugins is done by requesting them via UMC.
*** This bug has been marked as a duplicate of bug 54515 ***
UCS 5.0-2 has been released. https://docs.software-univention.de/release-notes-5.0-2-en.html