$ git clone -n https://src.fedoraproject.org/rpms/rubygem-actionmailer.git /var/lib/mock/f39-build-1813029-41834/root/chroot_tmpdir/scmroot/rubygem-actionmailer
Cloning into '/var/lib/mock/f39-build-1813029-41834/root/chroot_tmpdir/scmroot/rubygem-actionmailer'...
$ git fetch origin c817213ee661b31ecf016272bedd49f3735a0a7f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-actionmailer
 * [new ref]         c817213ee661b31ecf016272bedd49f3735a0a7f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c817213 Update to actionmailer 7.0.8.