@codesections Note that copyleft-next was started in 2013 or late 2012, and that the latest release 0.3.1 came out in 2016 and is still a work in progress.

The proprietary relicensing poison pill is not the only interesting feature, it also has a 15-year sunset clause for the copyleft preconditions, making a release permissive after that, in order to cure license incompatibilities and allowing code to move forward in terms of licensing without contacting every single author that ever contributed.