Question regarding the "activity" tab

[TheDreadPirate]

You cannot clear the activity logs in the UI, but you can change the retention by editing system.xml and running the activity clean up job.

Windows: C:\ProgramData\Jellyfin\Server\config\system.xml
Linux: /etc/jellyfin/system.xml
Docker: /config/config/system.xml (wherever you have /config mounted)

Edit the ActivityLogRetentionDays line to however many days you want to retain (default 30). Setting it to 0 will clear all activity logs. Restart jellyfin and then run the activity clean up job.

If you just want this to be a one time clean up, you will need to edit the file again setting it to however many days you want to retain activity logs and restart jellyfin again.