Is git pre-installed on macOS Sierra?
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.