The core seems to have a lot of interesting features, and even though it was developed for his plugins, the dev was kind enough to give examples, share the source, and even show it in action.
I dont know if it works or not on 1.14 , but thats certainly not the way of asking for support or reporting an issue.
The person below is just rude and unfair in my opinion.

NOT WORING ON 1.14.2!!!!! PLEASE FIX IT NOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I was about to start making my own API for my purposes until I found this. This API is very useful, thank you very much for making it!