The ATG Control Center includes UI components for creating repositories queries. For example, the People and Organizations > Profile Repository window displays an expression editor for composing queries on the Profile repository like this:

List Items of type User whose Gender is female

Note: ATG Control Center limits the number of items that can be returned by such queries. This limit is configurable and is set in the maxQueryCount property of /atg/devtools/RepositoryAgent. The default value is 1000.