Your comments

Well... I guess he made it a bit too easy to get most of the features one may need. So, why bother paying. Or, he should have made it donationware, etc. with some prompt popping up from time to time encouraging to give support (not necessarily a fixed price). VB-Audio (voicemeeter) guy does just that and - I think - he does not complain.

So, if out TO author got frustrated or something - maybe he should re-think his busi9niess strategy.. hmmm....

@Boris: What about just now (for the past few days)?

By the way: I am currently at Chromium ver. 89.0.4389.90 (Official Build) Arch Linux (64-bit)

@Hikari: OH YEAH! That's what I was hoping for. Got it all back. Thank you so much.

I sort of expected major issues with TO at this time, but let me put it in a separate thread.

@Hikari - thank you very much. I perhaps forgot that I actually got something in a form of an URL along with the license. It seemed to somehow work "automagically". I will look for it in my email. 

Still - quite sad TO developer did abandon his werk of art. So many people would be happy to support him (also financially, I presume) if he wished to continue.

Well, well... I am not sure what happened, but I updated Chromium to the latest version and the browser said that TO extension is damaged. Needed to be "repaired". Went ahead with the repair process and it now works again. BUT! Invites me to pay for the extended features again. It does not believe I already did that in the past. Any way to rectify this?  

Not to mention that I suddenly started experiencing the multiplication of tabs in groups. Maybe I must stop Chromium from restoring the tabs on startup.

Except... this is hardly a solution. As the author stated: more of a [temporary] workaround.

TO developer / maintainer should issue a proper fix for this.

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).