General guidance for the Appendix D (Classified Appendix) includes:

When Does a DCR Need a Classified Appendix?

When only a small subset of the DCR needs to be protected at a higher classification level.

If the document is not useful without this appendix, the document is to be classified at a higher level.

A classified appendix's content counts toward the document body page limits and must be indexed to align with the baseline document sections.

Except where the existence of classified content cannot be acknowledged, each section of the baseline document augmented by the classified appendix must refer the reader to the classified appendix.

If used, the appendix will be provided to the Joint Staff Gatekeeper or J-8/SAPCOORD IAW its classification level.