1. The text is redundant with the Figure title:

2155 Variable header non normative example
2156 Figure 3.21 shows a variable header with Packet Identifier set to 10. 2157

2159 Figure 3.19- Variable header with a Packet Identifier of 10, Non normative example

2. Minor edit - The context is set in the first sentence so the "SUBSCRIBE pakcet payload" does not need to be repeated in the second sentence:

2173 The payload of a SUBSCRIBE Packet contains a list of Topic Filters indicating the Topics to which the
2174 Client wants to subscribe. The Topic Filters [in a SUBSCRIBE packet payload] MUST be UTF-8 encoded
2175 strings as defined in Section

Suggestion:

The Topic Filters MUST be UTF-8 encoded.

3. Missing comma

2179 characters[,] it MUST reject any Subscription request whose filter contains them

4. Redundant not used and reserved

2210 Bits 6 and 7 of the Subscription Options byte are not used, and are reserved for future use.

Suggestion:

Bits 6 and 7 of the Subscription Options byte are reserved for future use.

5. "if" rather than "is"

2188 ... It is a Protocol Error [is] the