2.6. Appendices. The appendices for an IS-ICD are the same as for a regular ICD.

For reference or comparison, below is what the JCIDS Manual says for the ICD 2021 itself:

2.6.2. Appendix A. References. Ahead of other references provided in this appendix, provide an accessible URL for required architecture data and associated artifacts/views identified in Figure B-28 and, if applicable, Figure B-31.