<ctrl-t> bgp <enter>
A project page for a $language implementation of $protocol shouldn't be expected to give a basic description of $protocol. If you care about a new implementation, you already know what the protocol does, at least generally. If you're lucky, the project page links to a protocol description (possibly at wikipedia), or, as above, you can simply google it yourself and then decide whether a $language implementation of it is something you care about.