$ git clone -n https://src.fedoraproject.org/rpms/ghc-echo.git /var/lib/mock/f45-build-10234-414/root/chroot_tmpdir/scmroot/ghc-echo
Cloning into '/var/lib/mock/f45-build-10234-414/root/chroot_tmpdir/scmroot/ghc-echo'...
$ git fetch origin fb2d36a4238fcd4cdd293ebe9159a15f0b831131:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-echo
 * [new ref]         fb2d36a4238fcd4cdd293ebe9159a15f0b831131 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fb2d36a Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild