This is great. Now we are free to help remove dependencies, improve this engine and in the long run hopefully help Valve take further steps into being a more Open Company , I hope that Valve change the license once they are in a position to do so. They are in a staggeringly odd turn of events starting to 'Open Up ' and working within the view of the outside public on a number of high profile software projects. They are making good moves, I for one intend to encourage them to make more by helping! Pull requests to help them will make them realize they will gain more if the engine is even more open, its a matter of time.

And specifically to the people complaining about the license file https://github.com/ValveSoftware/source-sdk-2013/blob/master... . The likely reason that it cannot at this time be changed will probably be the legal agreements Valve has signed regarding the stuff you will read if you open up one of the other files up in the root of the repo thirdpartylegalnotices.txt https://github.com/ValveSoftware/source-sdk-2013/blob/master...

Edit--- It looks like people are already hacking away and fixing stuff! https://github.com/AnAkIn1/source-sdk-2013/commit/fe2fa2204b...