I fully agree.
My idea would be to help contributors to understand where to go translate each project
upstream.
The Language-Team attribute probably is good enough to lead a contributor at the right
place, here are a few examples for French language:
0ad: "Language-Team: French
(
http://www.transifex.com/wildfire-games/0ad/language/fr/)\n"
ABRT: "Language-Team: French
<
https://translate.fedoraproject.org/projects/abrt/"
Apstream: "Language-Team: French
<
https://hosted.weblate.org/projects/appstream/"
Audacious: "Language-Team: French
(
http://www.transifex.com/audacious/audacious/language/fr/)\n"
Gnome shell: "Language-Team: GNOME French Team <gnomefr(a)traduc.org>\n"
Krita: "Language-Team: French <kde-francophone(a)kde.org>\n"