by Ken Task.
If you are still attempting to download and restore backups from that HUB, the site has issues and has debug turned on. As a result, when you click on the button to download a course backup (a .mbz file) it will download. Once downloaded and attempting to inspect the contents with command line tar -vft [nameof].mbz
That will return
tar: Unrecognized archive format
tar: Error exit delayed from previous errors.
every time. That command should list the contents of the .mbz file.
Using:
head -n 10 "Health 8.mbz"
one finally discovers why ... it is an invalid .tar.gz backup.
Since the site is in debugging mode, this is what gets injected into the head of the file you downloaded:
<div class="notifytiny debuggingmessage" data-rel="debugging">add_to_log() has been deprecated, please rewrite your code to the new events API<ul style="text-align: left" data-rel="backtrace"><li>line 48 of /lib/deprecatedlib.php: call to debugging()</li><li>line 66 of /local/hub/webservice/download.php: call to add_to_log()</li></ul></div>P?N?H
Thus, not a valid backup file from which Moodle can restore.
HUB site administrator needs to turn off debugging.
'spirit of sharing', Ken