How to deploy Unity apps to Desura, and submitting the Mac builds as DMG files. It has to be done from a Mac.
Desura publishing group is a group dedicated to all questions regarding game & mod publishing on Desura, also a place where you can write your own game and mod requests.
For latest general news about newly added games and mods you can specifically have a look at this group.
Official features and updates on publishing progress, plus various articles about technical limitations including FAQs and tutorials familiarising you with the publishing process itself, may be found here as well.
Publishing on Desura: Desura.com
How to publish your game/mod on Desura: Desura.com
Tutorials, issues, troubleshooting: Desura.com
Publishing content: Trac.moddb.com
Creating MCFs*: Trac.moddb.com
Uploading MCFs*: Trac.moddb.com
*MCF is a Desura archive file containing a specific game/mod release.