Minor TAB-1570 - Patrick Durusau
This is a follow-on from my comment about conformance clauses needing to invoke more that the MUST statements in the specification.
If you agree that the non-highlighted but normative text is also important for conformance, then the yellow-highlighting of MUST statements is distracting at best and mis-leading at worse.
No conforming use of MQTT can be constructed reading only the highlighted text so why bother? Non-normative text should be marked (as you have) or put in comments or examples.
You wrote normative prose to define MQTT so why not require people to read all of it?