These are only cached in your client.
The only way to backup these in TS3 is to move these to the local area. But then these are no longer synced and only stored in Client’s settings.db in path %AppData%\TS3Client Windows.
Right click on a bookmark or identity > Duplicate.
Right click on a bookmark or identity > Move to local
Ps in the theme you use the local area is very hidden. At the bottom of the dialog should be 3 dots which can be moved to top and will open the local area.
