EllisLab/CodeIgniter — comment on commit f4a4bd8fac188ebc9cda822ffc811c218fd92b45
File:  line 0
By derekjones:

OSL = [Open Software License 3.0](http://www.opensource.org/licenses/OSL-3.0)
AFL = [Academic Free License 3.0](http://www.opensource.org/licenses/AFL-3.0)

The Academic Free License is identical to the Open Software License except for the latter portion of section 1(c). The Academic Free License allows distribution of original and derivative works "under any license of your choice that does not contradict the terms and conditions, including Licensor's reserved rights and remedies". We have applied AFL to the files we distribute in the application folder (Welcome controller, error pages, config files) so that changes to those files do not burden you with having to make them available as OSL licensed code.

We refer to this in laymen's terms as: The Application folder is *yours*. Only the CodeIgniter system and ancillary files utilize the generous copyleft OSL license.

Here's a nice FAQ written by the author of both licenses: http://www.rosenlaw.com/OSL3.0-explained.pdf