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.