$ git clone -n https://src.fedoraproject.org/forks/packit/rpms/rubygem-git.git /var/lib/mock/f41-build-60939733-6586469/root/chroot_tmpdir/scmroot/rubygem-git
Cloning into '/var/lib/mock/f41-build-60939733-6586469/root/chroot_tmpdir/scmroot/rubygem-git'...
$ git fetch origin 05d8986dc5ee5b165349ec594d3804057c7fd372:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/forks/packit/rpms/rubygem-git
 * [new ref]         05d8986dc5ee5b165349ec594d3804057c7fd372 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 05d8986 Update to 4.0.1 upstream release