Is Ethereum open source?
I've heard different things from different people.
Stephan Tual has written:
"Everything at Ethereum, including our website, our tools, our whitepapers and of course our all of our software and compilers are 100%, wall to wall open source and under the GPL."
But then what about the Ethereum Foundation?
How does the open-sourceiodicity of Ethereum compare to that of Bitcoin? How does it compare to that of the proposed "private blockchain" Hyperledger project?