The modify headers addon is distributed with a MPL license. http://modifyheaders.mozdev.org/
I think it's code-embedded in the file modifyheaders-services.js http://www.mozdev.org/source/browse/modifyheaders/src/components/modifyheaders-service.js?rev=1.8;content-type=text%2FplainAnyway, most of the addons on mozdev.org seem to have this license, as stated here:
http://www.mozdev.org/copyright.html Regards, -- Federico Bruni | http://www.gnurag.net/blog/ LibrePlanet Italia http://groups.fsf.org/wiki/LibrePlanetItalia -- http://gnuzilla.gnu.org
