Puntuado con 4 de 5 estrellas

The browser-support message can be avoided using the general.useragent.compatMode.firefox config preference. Good addon, though. I'm not sure if this issue can be avoided, but I'll keep at 4 stars in the meantime.

Puntuado con 1 de 5 estrellas

Doesn't work. Says browser isn't supported.

Hi Andre, make sure you have Firefox version 122 (which is set for extension) and above, for more about Slack browser support;
https://slack.com/intl/en-gb/help/articles/1500001836081-Slack-support-life-cycle-for-operating-systems-app-versions-and-browsers