There are quite a few settings one can fiddle with at the repository level. To access these settings, search for the wrench icon on the right sidebar:
The default branch of a repository's main page is master. However, there are times when you want a different branch to be your default, based on one's workflow as we saw in Chapter 4, Collaboration Using the GitHub Workflow.
Let's just say, for example, that the master branch is where you push code that is considered stable and well-tested, whereas you have a different branch named develop that is used for daily pushes and testing new features. Based on this assumption, the develop branch gets updated more often than the master branch. Practically, you'd want your project to seem active; having a branch that gets updated every day in the front page is much more appealing.
In this case, you can go to the repository's settings page and choose the branch you would...