OK, I have found the problem. It is in the package language-pack-gnome-en-base
$ dpkg -l language-pack-gnome-en-base|tail -1
ii language-pack-gnome-en-base 1:10.10+20100817 GNOME translations for language English
When I do an apt-get source language-pack-gnome-en-base, I get the source, in which is the file data/en/LC_MESSAGES/yelp.po which, other than the header and footer, is identical to ./data/en@shaw/LC_MESSAGES/yelp.po .
My solution would be to replace data/en/LC_MESSAGES/yelp.po with the more standard yelp.po from the data/en_GB subdirectory. There are other solutions as well.
OK, I have found the problem. It is in the package language- pack-gnome- en-base
$ dpkg -l language- pack-gnome- en-base| tail -1 pack-gnome- en-base 1:10.10+20100817 GNOME translations for language English
ii language-
When I do an apt-get source language- pack-gnome- en-base, I get the source, in which is the file data/en/ LC_MESSAGES/ yelp.po which, other than the header and footer, is identical to ./data/ en@shaw/ LC_MESSAGES/ yelp.po .
My solution would be to replace data/en/ LC_MESSAGES/ yelp.po with the more standard yelp.po from the data/en_GB subdirectory. There are other solutions as well.