@leocg If, like you said, I disable browser.js and log in, twitch will simply collect my 2FA code and then refresh the page.
This then sends me back to the twitch home page, not logged in.
If I keep browser.js turned off and try again, it just does the same thing again, if I turn it back on at that point and try to log in, it will still tell me that my browser isnt supported.