Ok I learned any-jump.vim uses gpl-licensed data from dumb-jump.el, also this explains how it works, it's literally a copy paste of the regexes with some vim ui magic.
I added my naive implementation of AnyJumpFirst: https://git.sr.ht/~razzi/any-jump.vim/commit/84110904fab7ce06c8d4487d76c933c2ae66173a
Kinda tired of vim, the script is really crap, especially since just now I tried to remap my function to g] but it simply doesn't work...?
I also updated my article about weechat to include smart filtering and autojoin. Good stuff, irc is looking better by the decade...