$ git clone -n https://src.fedoraproject.org/rpms/rubygem-aruba.git /var/lib/mock/f40-build-2136696-50815/root/chroot_tmpdir/scmroot/rubygem-aruba
Cloning into '/var/lib/mock/f40-build-2136696-50815/root/chroot_tmpdir/scmroot/rubygem-aruba'...
$ git fetch origin 99d8062c61802d50342651e32f4f640897c9d218:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-aruba
 * [new ref]         99d8062c61802d50342651e32f4f640897c9d218 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 99d8062 fix date...