Hello Stefan,

Thank you for your thorough review.  I'm rather new to Emacs Lisp, and
also to the Emacs development workflows, so this is highly
appreciated.

Here I've attached a new version of the patch.
 - Copyright notice is now as it should be (now that the paperwork
   permits it)
 - All the stuff you suggested to be removed has been removed
 - The test has been renamed as suggested

In one place I've changed your suggestion:

> For now, I think you should simply place the file directly at:
>
> lisp/progmodes/cperl-mode-tests.el

I guess this was meant to read test/lisp/progmodes/cperl-mode-tests.el.

Also, I've added a ChangeLog-style attachment, as suggested by Lars
Ingebrigtsen in his comment to Bug#42355.
--
Cheers,
haj