package.xml: md5sum attribute of <file />

I looked at the archive, seems it doesn't go back enough in time, hence this question: what purpose does <file md5sum="..." /> fill that wouldn't be satisfied by checksumming the whole tarball? -- If you cc me or remove the list(s) completely I'll most likely ignore your message. see http://www.eyrie.org./~eagle/faqs/questions.html