$ git clone -n https://src.fedoraproject.org/rpms/python-rosinstall_generator.git /var/lib/mock/f39-build-1425929-31585/root/chroot_tmpdir/scmroot/python-rosinstall_generator
Cloning into '/var/lib/mock/f39-build-1425929-31585/root/chroot_tmpdir/scmroot/python-rosinstall_generator'...
$ git fetch origin 2d9e3abc4db3cf12227cf34896b6bba347362b83:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-rosinstall_generator
 * [new ref]         2d9e3abc4db3cf12227cf34896b6bba347362b83 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2d9e3ab Update to 0.1.23