Thunderbird will support matrix protocol out-of-the-box in version 102 (due June) and is available in v91 beta now.
I just tried it, you go to preferences, edit config, add a string “chat.prpls.prpl-matrix.disable” and set it to false and matrix becomes an available option in the chats part of your account setup…now to find my old password…
I wonder if they implemented it with one of the Rust libraries or just implemented it in JavaScript. I can’t imagine that they would want to implement it in C++, given the history of problems there.
“prpl” (protocol plugin) is the term used in libpurple for a plugin, so it would appear it’s using libpurple as the backend, thus purple-matrix; however, that plugin is deprecated as of a week ago.
edit: I was mistaken, it appears to be using the javascript SDK.
Thanks for the sleuthing.