It would be great if d-i was able to handle extra translations
provided in udebs, to make it possible to add translations to udebs
after they are released. To make this possible, I believe udpkg need
to use the --merge argument to debconf-loadtemplate when installing
udebs.
Here is an untested patch to make this happen. I've not commited it
as it is not tested, and I lack a test framework for d-i at the
moment.
Index: debian/changelog
===================================================================
--- debian/changelog (revisjon 29315)
+++ debian/changelog (arbeidskopi)
@@ -7,6 +7,9 @@
[Petter Reinholdtsen]
* Remove myself as uploaders. Leaving this package to others in the
debian-boot team.
+ * Use --merge by default when calling debconf-loadtemplate, to
+ make it possible to append new translations to d-i by providing
+ udebs with only the new translations in them.