module T::Private::Abstract::Hooks

is important for our validation).
`included` hook, but this gets calls before the ancestors of `other` get modified, which
It gets called when *that* module gets included in another class/module (similar to the
This will become the self.append_features method on a module that extends Abstract::Hooks.

def append_features(other)
vate::Abstract::Data.set(self, :last_used_by, other)