Is git pre-installed on macOS Sierra? I am very new to macOS, knowing Ubuntu a little bit, and am wondering whether git is pre-installed on macOS or not. Typing

which -a git


results in 

git is /usr/bin/git


But when I init a test-repo and checkout a myBranch, the command 

git branch


results in a empty line. So is there anything I do forget? I installed Homebrew before checking for git, so maybe this causes some interdependencies?
macOS does come with a binary at /usr/bin/git, however by default it's a wrapper around the command line tools installer. Running the command will print the following and return immediately.
note: install requested for command line developer tools

A prompt will ask the user to install the command line tools, with a button that downloads and installs the toolset.

Once installed, /usr/bin/git will be a proper version of Git compiled by Apple (noted by the ‘Apple Git’).
$ /usr/bin/git --version
git version 2.24.3 (Apple Git-128)

If Git is installed using Homebrew, it will be at /usr/local/bin/git by default on Intel, at /opt/homebrew/bin/git on ARM.