Yes, it’s indeed an open source project. I am publishing it as a Node Module too and also creating a Netlify Build Plugin to easily copy and deploy the functions. I’ve got promising results in most of the tests and was just able to overcome another limitation (discussed here).
I’m currently writing the documentation. The repo is here: https://www.github.com/Hrishikesh-K/OpinionJS/ and the documentation is here: https://opinionjs.netlify.app/. If someone does come across this as of now, don’t use it just yet. I’m constantly changing something, and more importantly, even the name is not finalized. So, a lot of breaking changes are expected. But if someone is willing to test and suggest changes, go ahead. I’d love to improve this thing as I think it might help many people solve a major problem on their static websites.