$ git clone -n https://src.fedoraproject.org/rpms/golang-github-prometheus-client.git /var/lib/mock/f39-build-2132211-50802/root/chroot_tmpdir/scmroot/golang-github-prometheus-client
Cloning into '/var/lib/mock/f39-build-2132211-50802/root/chroot_tmpdir/scmroot/golang-github-prometheus-client'...
$ git fetch origin 8a5074f34a61839040c258c36d48408863ec3ed2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-prometheus-client
 * [new ref]         8a5074f34a61839040c258c36d48408863ec3ed2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8a5074f Fix F38 build