$ git clone -n https://src.fedoraproject.org/rpms/ghc-regex-base.git /var/lib/mock/f45-build-10673-419/root/chroot_tmpdir/scmroot/ghc-regex-base
Cloning into '/var/lib/mock/f45-build-10673-419/root/chroot_tmpdir/scmroot/ghc-regex-base'...
$ git fetch origin fe1a4f0cec2ac7fa35462e265933c429615a9b8e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-regex-base
 * [new ref]         fe1a4f0cec2ac7fa35462e265933c429615a9b8e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe1a4f0 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild