Allow resource pack authors to change the grass/foliage color overlay/saturation values for different sub-seasons using a JSON file.

Since 2018, and we still can't change the color ourself =/
Goodbye our blueish winter.

Would this also make it so optifine/mcpatcher foliage/grass biome palettes will work? Since they don't right now :( Or do I need to open a separate issue for that?

Probably not? I mean, they override and change the same stuff we do. It does work with just vanilla textures, but IDK to what extent other resource packs affect it. But proper "compatibility" with OptiFine really isn't something we can do, as they're not open to working with other mod developers.

ah, too bad. Oh well.

I have just made a change that may fix Optifine compatibility, but no promises. If this doesn't work I honestly have no clue, and I can't really check easily either because of what Forstride mentioned.

If it doesn't work, it doesn't work. that's fine. Not like the end of the world ;)
Thank you for the effort, I will test when available.

I second this issue. Might I also add a suggestion to having a map that you could easily modify the colors to our liking?