MariaDB-10.1.21-centos6-x86_64-server.rpm fails to be included in repodata

This rpm isn't being included in the repo data:

https://yum.mariadb.org/10.1/rhel6-amd64/rpms/MariaDB-10.1.21-centos6-x86_64-server.rpm

The repo catalog:

https://yum.mariadb.org/10.1/rhel6-amd64/repodata/02f0db49b9eed6e4d6e980e0e3b487c4a6e4142192b4687a0247b69fdd84a92a-primary.xml.gz

The needed tags in the server rpm seem to be missing. When I download the rpm and run createrepo just on that one rpm, the catalog shows nothing, just as it is missing in the maria db yum catalog.