Adding on to Joseph612's sentiment, LayerX Security (tho not yet deep tested) has this add-on scored as Low Risk in their ExtensionPedia (their extension risk database).

That, and the "no permissions" declaration is pretty key here too. The add-on itself isn't handling any credentials, or any part of the auth process, it's providing a window for the user to interact directly with Proton services, which live on Proton's own servers (as would accessing Proton from the address bar in the main browser window).

TY Daskashk! Stoked to have the befitting Lumo to streamline into my LibreWolf setup!

Does what it says. Dunno what that other guy was saying about it being malicious but you can check for yourself by right-clicking 'Add to Firefox' and saving the link and throwing it into virustotal. In case you're lazy, virustotal reported Lumo by Proton Sidebar (v1.2) as "a simple wrapper" and "There is no executable JavaScript, background scripts, or other active code logic within the extension package itself. The extension's sole purpose is to display the Lumo by Proton web service in a browser sidebar." Appreciate the extension Daskashk :)

Works flawlessly! 👍

This add-on displays the Lumo AI website in the sidebar. That's why it offers the exact same behavior and functionality as the website does.