pull request functionality on git
Explanation:
There is someone else's repository repo A. If you want to contribute code to this repository, you must first fork this repo, so you have the same repo B under your own account.
Work under your own warehouse B, commit, push. Then you want the original repository master to merge your work, so you can initiate a pull request on github, requesting the master of repo A to merge the branch from his own B repository.