Works fine and according to its own description is highly optimized. But the font size is pretty small and not customizable. E.g. Tab Counter Icon is much better in this regard.

Needs to update text/numbers color on dark mode.

Najlepszy!

Thank you. Fast and helpful.

Does what it's supposed to do and nothing more. Neat.

works fine

Super useful for us, tab hoarders with 250+ tabs opened... This is kind of sad, but this extension is not to blame!. I recommend moving it from the address bar level to tabs strip and disabling it vis userChrome.css when you have non-overflown tabs!

Cool little helper. Informs me with the exact number of tabs open. THIS is what I wanted.
An improvement would be if I could define a number for alert notification. (even wording I enter :)
example: 20+ Hello, 40+ WaytoGo!, 60+ Caution!, 80+ Nuts!
I am at 108 right now, I need to come down.

Works as expected and the best tab counting add-ons I tried out