Advertise and explain how to use the bridges hosted on matrix.org

Bridges are the big selling point to many, and yet from the information included on matrix.org it may be hard to learn that they're actually running on the matrix.org homeserver, or figure out how to use them. Today there was a user on HQ that was sure that XMPP bridge is not supported. Looking at the website, I don't blame them:

https://matrix.org/bridges/#libpurple doesn't even mention XMPP, even though this is what we use it for.

If you dig up https://matrix.org/docs/projects/bridge/matrix-bifrost it mentions XMPP it mentions it as an open source project available on Github, but unless you go there and dig up https://github.com/matrix-org/matrix-bifrost/wiki/Address-syntax you won't even know that it's running on Matrix org.

This creates the perception, in some, that Matrix talks a lot about bridging and interoperability but doesn't do much about it.

Ideally there'd be a place on matrix.org that lists all the bridges, first party or not, reachable on matrix.org and basic instructions on how to use them.

Start by reviewing the bridges page at matrix.org/bridges/#libpurple and the linked matrix-bifrost documentation, including its address-syntax wiki page. Done means matrix.org identifies the bridges reachable on its homeserver, explains supported protocols such as XMPP, and provides basic usage instructions.