$ git clone -n https://src.fedoraproject.org/rpms/golang-github-armon-metrics.git /var/lib/mock/f38-build-side-42-init-devel-683229-26747/root/chroot_tmpdir/scmroot/golang-github-armon-metrics
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-683229-26747/root/chroot_tmpdir/scmroot/golang-github-armon-metrics'...
$ git fetch origin 8c5f913c4e9bdb2d3207634a03816374f2448e4a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-armon-metrics
 * [new ref]         8c5f913c4e9bdb2d3207634a03816374f2448e4a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8c5f913 Rebuild to fix FTBFS