Good

Easy to use. Facile et agréable utiliser.

the browser is now reflected as firefox 56 and google drive/site are complaining : not supported. after disable, it shows again firefox 92

I just tested your extension with this site: https://www.deviceinfo.me/ and surprise it's not that good.
Here is the response from the site "Supports real browser kernel detection even if the browser is spoofed, for: Firefox, Chrome, Edge, Internet Explorer, Safari, Opera, Konqueror."

Works wonderfully, would recomend.

Let me download Windows ISO with ease

AVOID!!! - causes PC to crash as "unsupported browser" tabs open - especially if using Linux + Waterfox as UA etc (more than that)

USE LINUX kODACHI

Does what it is intended. However, I would prefer if the user agent selection is somehow limited only to the tab where it was selected.

Works great, just used to download the Windows 10 Media Creation Tool. Great for annoying websites that block downloads for other platforms.

If you are like me and just want a SIMPLE user agent switcher for a few sites, this is the one. Just go to the site you want to use, click on addon icon, "override for domain", select a link variation and you are done. I use it mainly on instagram desktop and I have tried 2 different similar addons before and they either didnt work, or were too complicated. I figured this one out in 2 seconds literally.

Edit: recently this addon began breaking outlook and twitch pages for me. This happens when its not set to "Default", but instead I set it to what I use "Windows / Firefox 83", and it broke many things on those pages to a point I was using a different browser. Just set it to "Default" when not in need of its services.