According to the White House Central Files manual, this category was for "material pertaining to international relations or in connection with the plans, policies, procedures and programs, regarding foreign countries or governments ... (including) matters relating to the administration of foreign affairs; economic development; mutual security; and foreign information and exchange activities."
Specific exemptions are: ambassadors and others to the United States (see CO); international organizations (see IT); and medals and awards (see MA).
The researcher should note that most White House foreign affairs material, especially security classified material, was maintained in the National Security Council's filing system and did not enter the White House Central Files.