The ruleset root element has two attributes:
RuleSetName, for example, default_ruleset. This name is referenced in RuleSet to URI mapping.
Extends. This attribute refers to the inheritance feature of rulesets. The value points to the ruleset from which you would like to derive a ruleset.
Use the value none to signify that this new, independent ruleset does not depend on any other ruleset, or specify the <RuleSetName> to signify that your ruleset depends on another ruleset.