Returns a single reference from your Git database. The :ref in the URL must be formatted as heads/<branch name> for branches and tags/<tag name> for tags. If the :ref doesn't match an existing ref, a 404 is returned.

Note: You need to explicitly request a pull request to trigger a test merge commit, which checks the mergeability of pull requests. For more information, see "Checking mergeability of pull requests".
Get a reference