Ghost 12: how to reset the file/folder backup catalog?

I moved to a new backup drive and wanted to restart my backups strategy from there.

I removed previously made file/folder backups as they were of no use anymore.

However, I can still browse via the restore facility through all outdated files as if they are still recoverable.

Only on using them Ghost detects they do not exist anymore.

What is the best way to reset the catalog file to an initial state?

And how can I reset the backup history overview as there seems no way to delete entries of outdated backups?