by Ken Task.
That's odd!
If one can restore, the backup on the same server without error but not download the .mbz file ... that's really strange.
Gotta ask ... how are you downloading?
Locating in moodledata/filedir is kinda involved ... making DB query to find file by filename extension ... .mbz ... and contenthash.
Then with whatever you have to browse files, in moodledata/filedir/ do a find for the 'contenthash' value.
Will be in something like:
moodledata/filedir/xx/yy/xxyybunchoflettersnumbers
where xxyybunchoflettersnumbers is the contenthash seen in query.
'SoS', Ken