Summary:
The document is easy to read and in a good shape.
I have some minor concerns about this document that I think should be resolved before publication.

Comments:

The document is quite good and easy to read. My only concern is the security considerations that are rather brief.

Major Issues:

No major issues found.

Minor Issues:

The Security considerations might need more details.
Are there any concerns about incorrect metadata? What are the consequences of metadata being wrong intentionally, or by accident. When should integrity protection be used?