Though to be fair, we've all seen that kind of thing in the code and just left it well alone rather than pull on thr string and own the broken pieces you'll be handed for you trouble.
It's somehow horrifying that the unnaturally animated corpse of something that was so cool at the time like MSN Messenger lives on in an abomination like Teams.
Nothing much remains of the original protocol besides the name (MSNP), however; it started out being an IRC-like text-based protocol that MS even submitted to the IETF --- but never reached RFC status[1] --- but in its later years became gradually "XML-ized" and required more and more complexity in the client. The latest major revision of the protocol, which is also what the "new" Skype uses, is basically an HTTP API and thus most suited to being used in a browser, but definitely hinders those wanting to write a native client for it.
Though to be fair, we've all seen that kind of thing in the code and just left it well alone rather than pull on thr string and own the broken pieces you'll be handed for you trouble.