Forge Service Provider Interfaces
Service providers, and other global API-like elements, separated so dependencies don't need to be on the core forge system.
net.minecraftforge.api.distmarker.*are theDist/OnlyInannotation pair, used to identify elements that are only present in one of the two common distributions.net.minecraftforge.forgespi.ICoreMod*are interfaces for communication between Forge and the coremod library.