Why does my 'git branch' have no master?

Most Git repositories use master as the main (and default) branch - if you initialize a new Git repo via git init, it will have master checked out by default.

However, if you clone a repository, the default branch you have is whatever the remote's HEAD points to (HEAD is actually a symbolic ref that points to a branch name). So if the repository you cloned had a HEAD pointed to, say, foo, then your clone will just have a foo branch.

The remote you cloned from might still have a master branch (you could check with git ls-remote origin master), but you wouldn't have created a local version of that branch by default, because git clone only checks out the remote's HEAD.

master is just the name of a branch, there's nothing magic about it except it's created by default when a new repository is created.

You can add it back with git checkout -b master.

To checkout a branch which does not exist locally but is in the remote repo you could use this command:

git checkout -t -b master origin/master

I actually had the same problem with a completely new repository. I had even tried creating one with git checkout -b master, but it would not create the branch. I then realized if I made some changes and committed them, git created my master branch.