It does literally what it says: fake user agent to bypass Microsoft intentional block (there're other add-ons that purportedly do that, but this one works out of the box and does not require a video tutorial). Don't expect it to fix Teams bugs or accomplish world peace.
Also, you may need to restart Firefox after installing the add-on (it wasn't functional for me until I did, and it even crashed Firefox).
By the way, the
official Teams for Linux Client mentioned has been long abandoned by Microsoft.

Calls work with video and sound on mac.

Unfortunately for me, this extension actually made teams meetings refuse to start with a "Sorry, we couldn't connect you" message. Removing this addon resolved the issue, but of course now I get less Teams features since Teams knows I'm on Firefox linux.

Tested the camera in meetings with the DEB version on Ubuntu 22.04.1

Solve my issue on Firefox Windows 11

Solved the problem perfectly

Needs fixing. When installed/activated, Teams in Firefox gets really, really glitchy. Scrolling resets you to several lines above and you can't view the latest messages.

not working as per expectation , once I enable this plugin , call gets enabled but my chat screen gets buggy ,,I can't see my recent chat

I love you man.

Works perfectly on Windows with Firefox Dev Edition

Works for group calls.
Screen sharing doesn't work, but that is expected anyways.

Super add-on!

It's like the Zoom Redirector add-on but for Microsoft Teams. Clearly we'd all be better off using free / open source software for online meetings, such as Jitsi Meet, and non-free JavaScript is problematic. However, not everyone are prepared to or able to boycott any meeting because it's using Teams.

Shame on Microsoft and Zoom for using dark patterns to bully people into installing their spyware, and equally many thanks to the developer of this add-on for helping Firefox users attend these meetings in their favourite browser instead.

Can't join group calls. Please fix this

Does not make the call function work. ("Sorry, we could not connect you.")

occasional issues, but still makes teams on browser more usable

Works well, including video and shared screen. Thanks.

Quick to update. Great little add-on

Das Verhalten ist verbessert, da man im Browser wieder an Teams Sitzungen teilnehmen kann. Jedoch öffnet die Erweiterung eine installierte Teams App nicht.

The behavior is improved, because you can participate in team sessions in the browser again. However, the extension will not open an installed Teams App.

Hat instant unter Windows 10 und auch unter Linux funktioniert - DANKE ich muss nicht diesen Chrome Mist und auch nicht die App installieren! :)