The pull request is just an alternative version of the patches linus used to receive via email. Git is equally well suited to both.
At this point I don't think the tool does all that much advanced stuff, but the focus appears to be on understanding git at a level required to understand the more advanced features... so actually more focused on the semantics of git than on specific workflows.
> But then you start talking about pull requests, which are not a feature of git.
Actually, they are[1], though github pull requests appear to be designed in a way that is not interoperable with the native feature.
[1] = http://stackoverflow.com/questions/9630774/how-to-make-pull-...
But then you start talking about pull requests, which are not a feature of git. They are specific to github (e.g. try finding a PR comment in the git repo).
Does the new tool help with advanced git stuff, or does it just serve the github workflow?