I loved this add-on for several years, after Mozilla removed the old Add-on engine and this emerged as a new alternative to the old add-on (whichs name I forgot). But development pretty much ceased (last update in 2020) + the performance is terrible, even on highend hardware. I then found out about "Simple Tab Groups", even with 1000+ Tabs this add-on doesn't struggle or slows FF down to a crawl like Panorama does.
Get Simple Tab Groups instead of this.

Please add an option to disable groups counter over toolbar icon.

generally good, although the experience is different from the original version. One issue I run into from time to time tho, is that it seems to be randomly hiding 1 tab that I open. It's pretty unpredictable when this will happen but you will suddenly find there's 1 tab missing that you can't find unless you dig into the "hidden tabs".

Please add option to disable groups counter over toolbar icon, and also ability for custom CSS on Panorama page.

It's Good

A tool that puts order on an unwieldy list of tabs for many different uses

Indispensable! Absolutely necessary!

Great simple tool for organizing tabs but unfortunately it doesnt automatically back up your tabs (??? why) so I lost all of my tabs from an accidental misclick of closing my main window :/

Not store auto-backups

indispensible. i literally won't use FF without it. as a professional developer, i can't understate how useful this addon is for keeping FF in line.

Having over 1,000 – 1,500 tabs opened on my 16GB ram PC for over a year, I find this add-on extremely helpful. Not too infrequently firefox just crashes without showing slowing-down symptom first. Other times disabling this add-on and enabling it a few second afterwards will usually solve the problems without losing any tab groups.
I have one feature to request. Having a dozen windows opened, each with several tab groups, I have on my taskbar a dozen icons with name labels. As it is, the name labels vary reflecting the name of the tab in that window I last visit. It would be more informative if , let’s say, a window contains a lot of tabs about health, the window name label on the taskbar retains and remain the name HEALTH I give for that window. The procedure to request a feature in GITHUB is over my head.