Currently it works fine. Don't know why people reported different 4 months ago.
It does cause issues: Youtube subtitles can't be displayed, Claude uploads are getting rejected.

Pessima su Android!

It literally doesn't work most of the time. Sometimes it randomly does, but mostly it just doesn't do anthing

Doesn't work anymore.

current version of 0.6.6 December 17, 2025 is broken on firefox 145.0.1. user-agent is not taking effect and noticed an error in debug-addon of firefox.
Reading manifest: Warning processing storage: An unexpected property was found in the WebExtension manifest.

was useful while it lasted

This worked until few days ago and then my YouTube videos will stop at 1.00 minute and then playback will crash

Stopped working. This is now absolutely useless, and no update seems to be forthcoming.

Does not function

This addon breaks youtube. After around 30 sec of playback the player stops and says "something went wrong"

This has so far not caused the dreaded Cloudfare veryifying loop that the agent switcher by ntninja does. I thought Cloudfare was just completely against agent switchers until I tried this one instead.

Very useful, thank you!

Works well compared to another UA switcher I've tried, the website whatismybrowser actually gets fooled by the custom UA string, when with the other, it says Firefox on Linux (what I am indeed using) but announcing that it's (ua string). Only one problem. On Firefox forks that use older Firefox versions, this add-on is completely unavailable. Wtf? This is why I have experience with other UA changer add-ons.