ISO/TS 10303-1778:2014-02 specifies the application module for
External library.

The following are within the scope of
ISO/TS 10303-1778:2014-02:

• definition of a library that is not included in the data exchange file;
• items within the scope of application module External source, ISO/TS 10303-1331;
• items within the scope of application module Plib class reference, ISO/TS 10303-1291.