https://github.com/sp614x/optifine/blob/master/OptiFineDoc/doc/shaders.txt#L472

https://github.com/sp614x/optifine/blob/master/OptiFineDoc/doc/dynamic_lights.properties

@LuigiHutch why is this bad? it will be a simple json file.

Because then that states that you 'officially' support optifine which I dont think is a great idea.

Will close this for now since optifine does not yet support data-aware entity lights.