$ git clone -n https://src.fedoraproject.org/rpms/boom-boot.git /var/lib/mock/f40-build-2208824-52141/root/chroot_tmpdir/scmroot/boom-boot
Cloning into '/var/lib/mock/f40-build-2208824-52141/root/chroot_tmpdir/scmroot/boom-boot'...
$ git fetch origin 6158ea11b6f11f5b063b902c046782e39c6b78d2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/boom-boot
 * [new ref]         6158ea11b6f11f5b063b902c046782e39c6b78d2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6158ea1 Add dependency on systemd version