The description is taken from the description added to a page. You can see the description field field when you create a page or edit its title and properties and see the description section.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items