$ git clone -n https://src.fedoraproject.org/rpms/rubygem-actionmailer.git /var/lib/mock/f45-build-34767-691/root/chroot_tmpdir/scmroot/rubygem-actionmailer
Cloning into '/var/lib/mock/f45-build-34767-691/root/chroot_tmpdir/scmroot/rubygem-actionmailer'...
$ git fetch origin e8d0abb82f940921d2e39e1aeffaff73a3199b1b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-actionmailer
 * [new ref]         e8d0abb82f940921d2e39e1aeffaff73a3199b1b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e8d0abb Update to Action Mailer 8.1.3.1.