L0-R is a maximalist reciprocal open source software license that requires users who change your software, or use it to build other software, to share their own work back to the community as open source. In other words, L0-R makes your work "free for open source".
License Zero is an online platform for sustaining open software work by vending paid licenses to proprietary users. Developers using L0-R for a project can use License Zero to manage selling private licenses for them.
The License Zero Noncommercial Public License: a sister license of L0-R that limits commercial use to a free-trial period, instead of requiring release of open source. Similar to Creative Commons' Attribution-NonCommercial License, but for software.
The License Zero Permissive Public License: the modern, highly permissive open source license on which L0-R is based. L0-P is more in the vein of The MIT License or a BSD license.