This is roughly PHP’s approach. In this case, Illuminate is the vendor prefix and Mail is the package name. This often but not always corresponds to the rules around the composer package name, which would be illuminate/mail in this case.

This is similar to NPM’s organisation prefix (@foo/bar).

But yeah, I’m not defending the hacky way namespaces are resolved through autoloading. I do prefer actual language support for a module system (but Ruby suffers from this problem too).