Hey, i'll like to be able to add my own block of leaves that you can pass through, bcs since its not compatible with Biome You'll Go, i'll like to add his leaves.

ik, that's literally why i ask this ._.

Leaves are only passable if they follow correct programming practices, in this case BYG follows basically none as it is a MCreator mod, have the mod developer switch to Forge and extend Vanilla's leaf block class