Style Format Rules Page
The Style Format Rules page provides design-time access to a View's ColumnView.FormatRules collection. Objects in this collection specify conditional formatting rules, which allow you to apply formats to column cells that match specified criteria. Each object identifies the target column, the rule type and other options.
The Add and Remove buttons can be used to add a new formatting rule to or delete the selected one from the collection, respectively. The selected rule's properties can be accessed using the Properties tabbed page. The Rule tab is designed to make it easier to customize the FormatRuleBase.Rule property's settings. Moreover, this tab additionally allows you to see a preview of the selected predefined style format and custom appearance settings as well.
See the Appearance and Conditional Formatting document to learn more.