Three minor language nits:
In section 5.2.3. Version 4 Signature Packet Format:
- Two-octet scalar octet count for following hashed subpacket
data. Note that this is the length in octets of all of the
hashed subpackets; a pointer incremented by this number will
skip over the hashed subpackets.
There needs to be a "the" between "for" and "following". Note also
the same problem one paragraph later for the item discussing the
unhashed subpacket data.
Throughout the document, references to RFCs are written
inconsistently. For example, there are 3 references to "RFC 1991"
(with the space), and 2 references to "RFC1991" (without the space).
I like it with the space, though I really don't care which way things
go so long as it is consistent. (It's not just 1991 - all the RFC
references in the draft are mixed between the two styles).
There are a few spots in the draft where "PGP" is used when "OpenPGP"
should have been used (when referring to the standard, rather than the
Section 2.3 (Compression) has one in the second paragraph.
Section 5.2.1 (Signature Types) has one in the discussion of the 0x13
Section 5.7 (Symmetrically Encrypted Data Packet) has one when
discussing "PGP's variant of Cipher Feedback (CFB) mode".