Bug#1057288: www.debian.org: use of wml::debian::translation-check header breaks translation of "Galician"

On Sat, 2023-12-02 at 19:24 +0100, Holger Wansing wrote:
> I just found (more or less by accident), that using the
> wml::debian::translation-check header in wml files breaks the
> translation of
> the word "Galician".
> So this counts for all pages but English.
> The result can be found on pages like
> 
> https://www.debian.org/releases/trixie/releasenotes.nl.html

I could be barking up the wrong tree here, but I'm wondering if this is
due to the webwml repository embedding an old version of the Perl
Locale::Language module, that still lists gl as Gallegan. The below is
all currently based on searching through the repository, and hasn't
been tested in anger.

template/debian/translation-check.wml does a bunch of 'use lib
"(../)*Perl"' to find local modules, specifically Local::VCS.
english/doc/manuals.defs in turn uses Locale::Language to produce the
list of links to per-language documents.

Each of those uses individually is innocuous enough, but in combination
they will lead to manuals.defs loading Perl/Locale/Language.pm from the
webwml tree, rather than the packaged version.

Regards,

Adam