Github pull requests are the mechanism by which contributors submit code for review and subsequent merging to a Github branch. It can sometimes be useful to grab a pull request as a branch in your local repository. This can be useful for example to diff with one of your local branches or to merge with one of your local branches.
To fetch a Github pull request, note down its number XYZ. Use this command to fetch it to a new local branch:
$ git fetch origin pull/XYZ/head:new_local_branchname
The pull request is now available locally as the branch