> I would like to contact the DD who sponsored the upload, but the changes > file only lists the name of the NMUer. How can I know who the sponsor > was?

Check the gpg signature of the changes (or dsc) file: $ LANG=en_US gpg --verify <file>

... or use `who-uploads sourcepackage' to do the job for you. p.s. who-uploads(1) is in the devscripts package.