Testing inbound feed requests using sourcetree

Question

This is roughly BitBucket , may or may not apply to others. And I would rather do this using SourceTree or any other GUI tool.

Suppose I have a repository izharaazmi/repoand someone forkswho creates their own repo, say developer/repo. Now after making the changes, he commitssends a pull request.

Now I want to check its presentation before I approve it and merge it into the main repository izharaazmi/repo. How can I do this in a simple way?

Since there may be tens or even hundreds of difference developers sending download requests depending on the size of the project, it is impossible to download each of them without adding a remote source for each.

Note: The Joomla community already manages this scenario on a much larger scale, however they are on GitHub, if that matters.