Cannot read 'backupbundle'

[gmmapowell]

I came to sparsebundlefs in an attempt to read my Mac backup from Linux (my Mac just died, so...).

I am able to mount the drive, which then gives me a directory "catalonia.backupbundle". When I try and mount this using sparsebundlefs, I find that it fails because it has the "wrong extension":

sparsebundlefs: /mnt/catalonia.backupbundle is not a sparse bundle (wrong extension): Invalid argument

It would seem that the expectation is that the bundles will have the extension sparsebundle, but presumably Apple changed this at some point.