$ git clone -n https://src.fedoraproject.org/rpms/claws-mail.git /var/lib/mock/f39-build-1928370-43069/root/chroot_tmpdir/scmroot/claws-mail
Cloning into '/var/lib/mock/f39-build-1928370-43069/root/chroot_tmpdir/scmroot/claws-mail'...
$ git fetch origin 52005cfcf1ce491299a8914abecf460cf667178f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/claws-mail
 * [new ref]         52005cfcf1ce491299a8914abecf460cf667178f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 52005cf Upgrade to 4.2.0.