You will find in bug #523583 instructions about the 2 in-product pages to be localized for the Thundebird 3 release planned this quarter. The files are on the SVN repository in your locale folder, preferably commit directly to SVN and once done, inform in this bug. Alternatively, you can attach the files to this bug (either individually or as a zip archive). If you attach individual .html files, please attach them with the plain/text Mime format. News and instructions affecting all locales will be posted and updated if necessary in the master bug (bug #523583) Thanks!!
done on r55104
Thanks Fernando, marking fixed