yeah... exactly.  This is kind of strange. I guess one can still get the paid version, but the author seems to be gone. Soo... where does the money go? Interesting....

All good, but the group cannot be opened from the Backup View. Which could be realized as a series of "open new tab" actions on all of the links in the group, I believe.

Confirmed operational. All is good now. Side question: it is possible to open a group from the local TO window. However, when a backup from GoogleDrive is opened it is different. One can open any individual link from a saved tab, but not the entire group as originally backed up. Why is that? (by the way: it was always like that - even before the Restore functionality stopped working).

You mean clues for the developer, right?

Not looking, I think. Had they been they would have responded by now. Could be the developers are no longer around? That would be quite sad.

Nothing changes. Still the same. Maybe it is some change in Google Drive API that broke T.O.  ?

Yes, it is a problem with restore feature as far as I can tell. Backup itself is OK.

One question arises, though: what good is a backup if you cannot restore it later :)

Same problem here. RESTORE not working any more. This is new - several days ago everything worked as expected.