I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. Summary: ready with nits I find the Security Considerations section of this document to be reasonable. I agree that there is negligible security impact from the changes described in this document. The capitalization is inconsistent for "DefaultValue" (in typeDeclarationGroup) vs "defaultValue" (most other places). I think this poses no technical problem as written, but it could lead to surprises if human-written XML is validated against the schema (assuming I am correct in recalling that XML is case-sensitive). Editorial: I found it difficult to identify the before/after differences in the schema fragments, especially when the quoted fragments are large. Perhaps someone more familiar with XML schemas would not have this difficulty. I noticed that in some but not all of the schema fragments, the "" and <"!-- /Extension -->" comment annotations are helpfully used to mark portions of the schema that have changed. Notably, in Figures 2 and 4, these annotations are missing. I would prefer that changes be shown in a "unified diff" style, but I know that is not idiomatic in the RFC format. It would also be a good idea to describe the "" annotations in the text, to orient the reader to their use in the schema fragments. In Figure 4, the indentation seems incorrect and confusing. In Figure 5, I found the inclusion of extension annotations in the "original" excerpt from the schema to be confusing. The preceding paragraph does provide an explanation, but I wonder if it could be more clear. Figure 1 lacks this issue. In case future documents make further revisions to the schema, perhaps the extension comment annotations should include the RFC number of this document so that a reader may distinguish which changes took place in which documents.