This recently popped into my head, but have you thought about publishing this library to OPAM? For my project I basically just coped over the code but this seems a bit redundant, especially if you create new features or bug fixes.

I'd be happy to help if possible, thanks again for doing this!

EDIT: I tried esy add @opam/ocaml-css-parser and the install was not successful, which is why I'm raising the issue.