How do I browse files in my `.backupbundle` backup? I am currently trying to access my Time Machine backups manually, because the Time Machine feature was a little to slow for me and I needed the finder search. Before Catalina this was possible with the .sparsebundle but since then not longer. Every time I double-click the .backupbundle it says "This resource is currently not available".

I wonder if there is a way to mount/open this file to browse my backups. I read that renaming it to .sparsebundle would work but I don't want to destroy my backups – we all know that macOS sometimes do things different from expected ^^.

My Backup is saved on an Airport Extreme by the way. Which still works pretty well!
Try right-clicking (or Ctrl-clicking) on the bundle in the Finder and choosing "Show Package Contents".