**FIXED**
See below and updated rating to 3 Stars as it still has some issues.

To be clear people, THERE IS NO OFFICIAL Google Messages for Web, not even a Chrome Plugin. Click on any of Googles official (by Google) Apps, Plugins, or Add-ons for additional things from them and see for yourself.

Using Firefox 71 just updated this add-on:
1) *No longer usable as there's no longer a QR code just an empty box.
2) **Send Feedback link is broken.

Ongoing problems prior to this update:
3) Does NOT retain Remember this Computer status.
4) Has no way to send long SMS messages as MMS nor the option to do so (This should be default in 2019 already).
*FIXED: I deleted all cookies related to messages.google and all google messages. Closed FF and rebooted PC. It now shows the QR code.

Only 3 stars because it still fails to remember settings and the MMS ordeal.

It's 2020 Oinksters get with the program this should easily be a 5 Star extension for crying out loud.

Edit: Corrected QR spelling, added additional problems.
Edit 2: Added 2 stars and additional information.

I hoped this extension would enable me to pair my phone with my computer, since the web interface doesn't work for me anymore -- but I get exactly the same result: my phone thinks it has paired, but the browser never actually connects. Not the extension's fault but I can't figure out what's going wrong. Waterfox 56.2.7.1 (64-bit) on Windows 10.