$ git clone -n https://src.fedoraproject.org/rpms/perl-Text-Layout.git /var/lib/mock/f42-build-side-1-3588588-46947/root/chroot_tmpdir/scmroot/perl-Text-Layout
Cloning into '/var/lib/mock/f42-build-side-1-3588588-46947/root/chroot_tmpdir/scmroot/perl-Text-Layout'...
$ git fetch origin 41fd1a6e9f269e7a88bd373761df94cea2267b89:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Text-Layout
 * [new ref]         41fd1a6e9f269e7a88bd373761df94cea2267b89 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 41fd1a6 Update to upstream.