> fine, however you could take the exercise further and actually apply
> some of the functionality of L3PL. i've appended my version below

Thank you for your example.
At least I now understand (roughly)
what all the philosophical discussion was about.

However, I am still puzzled by the purpose of it all.
The new xr.sty is manifestly more difficult to follow
than its predecessor.
So who is meant to benefit ?
The user, the package writer, ... ?
And what exactly is the benefit ?

(I'd be grateful for an explanation not using the word "module",
which makes my head dizzy.)