If you have Open WebUI (or SillyTavern or something) running, you can just put the URL into browser.ml.chat.provider in about:config.The sidebar just loads and displays a webpage (ChatGPT or whatever) anyway.
Hello! I think that while this can present a security risk, it will also be a huge QoL improvement if Mozilla enables this. To mitigate the security risk, it could be made so that it can be enabled/disabled on a per-website basis and/or via a global ...