Rational is simple. Currently, addons submitters say what license the .xpi is supposed to be distributed under, but usually only a few files in the .xpi have the appropriate license information. The rest is in the legal limbo; also images are usually hard to add a license header to. Simplest solution is to require addons authors to include a license file in the .xpi top level directly which documents which license is applicable for which files in the .xpi. This would help to make the licensing more explicit, which is usually a base requirement for redistribution; for instance, we tried to contact various authors for licensing info, but usually they are not as responsive as we would like them to be. Its just easier to enforce the existence of proper licensing when reviewing new uploads to AMO imo than afterwards begging the authors to add that info. Thanks for your help.
A duplicate in concept of bug 446361 and others, but I like the idea of taking it from the XPI rather than using (only) a dev control panel field.
I like the idea too -- we should discuss it in Q1. I personally believe it is not too much asked from authors to take a breath and think about licensing for just one second when writing an extension -- even if they end up going for the simplest option and retain full copyright. Of course, we'd need to make this process as easy as possible for them, for example by providing/pointing to license boilerplates that they can just copy and paste.
Seeing as the license is really pertinent to the source itself anyway, it makes more sense to require information to be added with it than via AMO. Anything added with the dev control panel would be secondary. (i.e. translations?)
Thanks for your support on this so far. What we require in ubuntu is a complete license text file in the top level directory ... further I would suggest some short info in the .xpi install.rdf so it can be easily displayed in the UI. I don't think that we need to parse the license text file and generate the UI representation from that for the first step (which this bug is aboute); however, i agree that it would be a good extension of this approach at some point.
AMO already provides a mechanism to specify the license under which each XPI is released. I don't think it would be such a good idea to require authors to include one more file into their XPI only to qualify to be public. Most do pretty well in terms of licensing, and files without it should be considered as copyrighted by default.