From the site:

The CSL ("Cooperative Software License," "Communist Software License") is a Copyfarleft license that can be used for software and other cultural works. It follows along the lines of the Peer Production License, but with added stipulations on software's redistribution.

TL;DR, it's copyleft, but with one added restriction: You cannot sell the licensed work as a "traditional company" (anything other than a non-worker-owned cooperative). You can only commercially redistribute licensed works as an individual or as a worker-owned cooperative.

It's a commie license <3