The bulk of the items in the Confederate Citizens file are scans of vouchers, front and back, for items, animals, food (for man and beast), raw materials, services, or rent paid for by the Confederate government. Occasionally there is correspondence, including requests for appointments, letters of recommendation, letters from citizens in various locales to Confederate officials, and even personal correspondence. The most confusing items, however, are cross reference cards referring to other collections at the National Archives.
Today Trevor K. Plante, Textual Archives Reference at the National Archives, answered my questions about the specific locations for some of these collections.
"1. The slave rolls are found in RG 109, Entry 57, Slave Payrolls, 1861-1865.
2. Vessel Papers are reproduced on Microfilm Publication M909.
3. The personal papers listed with a person along with rank and regiment will be found in that person's compiled military service record. [Note: These are also available within Footnote.com.]
4. The Chapter/Volume records are found in RG 109, Entry 3, Collected Record Books, of Various Executive, Legislative, and Judicial Offices, 1860-65.
All of the above records and microfilm publications are located at the National Archives Building in Washington, DC."
I would only add that the personal papers that do not refer to a person with rank and regiment seem to mostly be within the Confederate Citizens file itself.