I updated my website to the latest oxcaml-5.2.0-minus39 and made some notes about how the opam packaging works https://anil.recoil.org/notes/oxcaml-opam-guards : this might be helpful if you're trying out the performance extensions with your own non-Jane Street codebases
Anil MadhavapeddyUpdating to the OxCaml 5.2.0-minus39 opam packagingHow the OxCaml overlay's guard packages keep incompatible releases out, and how to contribute to it with your own packages.