Queries return information about the data in your website, and in some cases you may not want that data to be public; in this case you shoudl restrict access to the queries. This is the purpose of settign the property 'May be Accessed by" to a value other than Everbody.
It accepts the same range of values as the variables property Editable By, including an manilafixer Message Level Access Control Cohorts. Before a query is evaluated by the query macro, the verbThisPage macro or from an RSS feed URL, the status of the client is checked. If the requester is not from the defined group, a macro error is taken, or for RSS urls a page inaccessible code 403 is returned.