Laurent Charignon has an very nice package for dealing with GitHub pull requests from within Emacs. His package, github-review, allows you to retrieve the pull request from GitHub and deal with it entirely within Emacs. You can even work off-line if you retrieve the pull requests first.
When invoked, github-review displays the description from the PR and a diff of the proposed changes. You can add additional comments or code snippets to the buffer. After reviewing the PR, you can accept, reject, or comment on it and have the results returned to GitHub.
Besides the obvious benefit of not having to leave Emacs, you can easily see related code to provide better context. If you often deal with PRs, this package seems like a real win. It’s probably worthwhile even if you only occasionally have to deal with them. The interface is simple and easy to use. Although Charignon says it’s not yet in Melpa, it’s been added since his post.