$ git clone -n https://src.fedoraproject.org/rpms/golang-github-appc-spec.git /var/lib/mock/f38-build-side-42-init-devel-857468-28427/root/chroot_tmpdir/scmroot/golang-github-appc-spec
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-857468-28427/root/chroot_tmpdir/scmroot/golang-github-appc-spec'...
$ git fetch origin dcaad3e89909833c103faa212d249a6e009ad765:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-appc-spec
 * [new ref]         dcaad3e89909833c103faa212d249a6e009ad765 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dcaad3e Rebuild to fix FTBFS