Selection can be by member name, library, language or date (all modules modified since the selected date) using the EXTRACT qualifiers MEMBER, LIBRARY, LANGUAGE and DATE. The selections can be used in any combination; the result is an AND of all the individual selections. By default all modules are selected.
This feature of EXTRACT makes it very good for distributing release updates. All the FORTRAN, INCLUDE and Document files can be bundled into a single file. This is then sent to any site that requires the release where the local librarian can use EXTRACT to split it back into its component parts.