LilyPond is the music engraving software used by the <score> tag. WikiSource (and, I assume, other wikis) currently run LilyPond version 2.24. The newest stable version is 2.26.
I’m relatively new to LilyPond and already I’ve run into a couple of significant bugs in 2.24 that have been fixed by 2.26. Worse, when I use Frescobaldi (LilyPond GUI editor) to preview my LilyPond, it renders fine and then breaks only after I paste it into a wiki.
What do we say we get LilyPond upgraded?