Looking at mods as recently as 1.13, there used to be a net.minecraftforge.common.Config package that appears to have made Config files pretty simple to produce and use.
In learning 1.14 I've had to sort of stumble my way to finding the new versions of old libraries/features, and so far, just looking at how vanilla classes do things has been enough. However I can't seem to find anything at all regarding config files. Are these libraries simply not implemented yet?