Answer
A geographical zone may prohibit flight, allow it with conditions, require notification, require permission, set a lower height, demand equipment such as geo awareness or remote identification, or apply only during certain times. The pilot needs the actual condition for the planned operation.
Explanation
Colour coding is a starting point, not the rule itself. Many zones are conditional rather than absolute. Reading the zone details prevents two common errors: flying where permission is needed, or cancelling a flight that would be allowed if the conditions were met.