As mentioned elsewhere in this discussion AdBlock is not Adblock Plus. The second link you posted is for the Adblock Plus source code.

Unfortunately at the moment the AdBlock Git repository is not public, but I have set up this unofficial one that tracks the changes between each zip published on their releases page. https://github.com/kzar/watchadblock

Specifically if you want to see what they've changed so far have a look at the last couple of commits https://github.com/kzar/watchadblock/commit/afff2b47024f3a55... https://github.com/kzar/watchadblock/commit/f1f52f47e276d29e...