$ git clone -n https://src.fedoraproject.org/rpms/ghc-serialise.git /var/lib/mock/f38-build-side-42-init-devel-1025622-29686/root/chroot_tmpdir/scmroot/ghc-serialise
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1025622-29686/root/chroot_tmpdir/scmroot/ghc-serialise'...
$ git fetch origin 29f92975c12ecb239e4e8f49ff5deccd40b22018:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-serialise
 * [new ref]         29f92975c12ecb239e4e8f49ff5deccd40b22018 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 29f9297 update to newer cborg 32bit issue