If you want to, you can easily add some seo metadata as done in:
https://github.com/symfony-cmf/symfony-cmf-website/blob/master/src/Cmf/MainBundle/Resources/data/page.yml#L89-L91
and add a the class for that:
https://github.com/symfony-cmf/symfony-cmf-website/blob/master/src/Cmf/MainBundle/Resources/data/page.yml#L83