$ git clone -n https://src.fedoraproject.org/rpms/pcm.git /var/lib/mock/f39-build-2553423-61951/root/chroot_tmpdir/scmroot/pcm
Cloning into '/var/lib/mock/f39-build-2553423-61951/root/chroot_tmpdir/scmroot/pcm'...
$ git fetch origin 4ed4a988fedbdc9acd6e6d1598c8e354e879ae29:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pcm
 * [new ref]         4ed4a988fedbdc9acd6e6d1598c8e354e879ae29 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4ed4a98 fix LINUX_SYSTEMD_UNITDIR