Titles from the v4 release notes [1]:

* A more global license
* Rights outside the scope of copyright
* Common-sense attribution
* Enabling more anonymity, when desired
* 30-day window to correct license violations
* Increased readability
* Clarity about adaptations

[1]: https://creativecommons.org/version4

This is up for discussion, but at the moment is the
minimal set of files needed to be a Software Carpentry lesson.