IRC linking is a mess, in part due to the spanning tree requirement. Also the server to server protocol in the RFC is spoken by zero servers so you have to pick which unofficial protocol you like best. May as well invent your own that actually fits your use case.

Except that now there's yet another standard, which nothing but this thing speaks. TS6 is very well used at the moment as everything in the Charybdis line speaks it, etc.