On OpenShift Online Service Catalog, the link to README.md points to a symlink instead the actual README.md file. It's the same link destination pointed by the "View Documentation" hyperlink.

The link is: https://github.com/sclorg/mariadb-container/blob/master/10.1/README.md

The actual file can be found in: https://github.com/sclorg/mariadb-container/blob/master/10.1/root/usr/share/container-scripts/mysql/README.md
The same goes to mysql-container.