$ git clone -n https://src.fedoraproject.org/rpms/regexp.git /var/lib/mock/f41-build-side-1-2824917-33350/root/chroot_tmpdir/scmroot/regexp
Cloning into '/var/lib/mock/f41-build-side-1-2824917-33350/root/chroot_tmpdir/scmroot/regexp'...
$ git fetch origin 6955e81a068e2ab2ea6776679db3849137b0d954:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/regexp
 * [new ref]         6955e81a068e2ab2ea6776679db3849137b0d954 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6955e81 Switch javapackages tests to f41 branch