$ git clone -n https://src.fedoraproject.org/rpms/ghc-pem.git /var/lib/mock/f45-build-10610-419/root/chroot_tmpdir/scmroot/ghc-pem
Cloning into '/var/lib/mock/f45-build-10610-419/root/chroot_tmpdir/scmroot/ghc-pem'...
$ git fetch origin efa5e2631ec89d715daf2aeed2568bd3b47caea1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-pem
 * [new ref]         efa5e2631ec89d715daf2aeed2568bd3b47caea1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at efa5e26 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild