$ git clone -n https://src.fedoraproject.org/rpms/rubygem-nokogiri.git /var/lib/mock/f39-build-1470325-33888/root/chroot_tmpdir/scmroot/rubygem-nokogiri
Cloning into '/var/lib/mock/f39-build-1470325-33888/root/chroot_tmpdir/scmroot/rubygem-nokogiri'...
$ git fetch origin 8820fad4b3e368c60c5cd255ce92b244133446ba:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-nokogiri
 * [new ref]         8820fad4b3e368c60c5cd255ce92b244133446ba -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8820fad 1.15.4