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."

HOW TF U PUT BIG "RESET TO DEFAULT" IN THE BOTTOM THAT EASILY CLICKED ACCIDENTALLY ? MORON OR IDIOT?

Works wonderfully, would recomend.

Let me download Windows ISO with ease

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.

It's very easy to use.

Works very well but the user agents have outdated browser versions.