This is not correct in a world with modules (I know we don't use them, but it's still a bad practice). It also complicates things like #2615, which assume a one-to-one correspondence from a package with classes to a Fabric API module.

This happens with some pairs of v0/v1 modules:

• Networking: impl.networking
• Rendering: impl.client.rendering
• Lifecycle events: impl.event.lifecycle