$ git clone -n https://src.fedoraproject.org/rpms/ghc-versions.git /var/lib/mock/f45-build-10945-425/root/chroot_tmpdir/scmroot/ghc-versions
Cloning into '/var/lib/mock/f45-build-10945-425/root/chroot_tmpdir/scmroot/ghc-versions'...
$ git fetch origin 42b760fe470fc7fd8671a9cf7b07ad4c967b496d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-versions
 * [new ref]         42b760fe470fc7fd8671a9cf7b07ad4c967b496d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 42b760f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild