$ git clone -n https://src.fedoraproject.org/rpms/guestfs-tools.git /var/lib/mock/f39-build-1505750-35160/root/chroot_tmpdir/scmroot/guestfs-tools
Cloning into '/var/lib/mock/f39-build-1505750-35160/root/chroot_tmpdir/scmroot/guestfs-tools'...
$ git fetch origin 07afab9d9745bbecc508cdcb525af43302868ce5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/guestfs-tools
 * [new ref]         07afab9d9745bbecc508cdcb525af43302868ce5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 07afab9 New development version 1.51.4