Where is log file of all activity log?

Hello everyone, sorry for my English.

I have a UCSServer 5.0-5 errata885 and have enabled NextCloud for file sharing. However, I have some questions like, where are the log files for all activities?

I can see the system logs in “/var/lib/univention-appcenter/apps/nextcloud/data/nextcloud-data/nextcloud.log” but it is extremely important to check the file change logs without using the gui.

I look forward to any help, thank you very much.