Just sticking this in Bugzilla as a reminder for further possible discussion, since it's been brought up or requested a couple times.
Scribus is an open-source, cross-platform desktop publishing package, which some folks like to use for things like brochures and other PR-type materials. It would be helpful to be able to share work in the original editable format.
The .sla file format is XML based, and can optionally be gzip-compressed direct from the app (saved as .sla.gz).
* Images can only be included by reference, not embedded. A complete document may require multiple downloads, or else manually zipping up the data set.
* Scribus files are XML, but there's not a doctype or xmlns requirement on the current version, so they might be harder to verify. (Root element is <SCRIBUSUTF8>.)