Hell if I recall the original purpose of it, but my dev-notes refer to that functionality for aliasing config sections, and the literal example is for repositories. I'm assuming this was the original support for repository ID aliasing before portage went in a different direction.
TL;DR: whilst refactoring repo configs, consider if this is useful as a concept to preserve/use. If so, use it. If not, punt it.
Hell if I recall the original purpose of it, but my dev-notes refer to that functionality for aliasing config sections, and the literal example is for repositories. I'm assuming this was the original support for repository ID aliasing before portage went in a different direction.
TL;DR: whilst refactoring repo configs, consider if this is useful as a concept to preserve/use. If so, use it. If not, punt it.