Unprecedented. There is no clear historical comparison — this changes the rules, not just the situation.
The definition the product enforces, read from the same code the methodology page renders.
Reserved for the genuinely unprecedented, where normal organizational playbooks do not apply at all. The rule when a read is torn between D and S is to use D; a scan is allowed at most one or two S classifications, and a very important D is still a D.
The weight of the decision an event forces on a party: two axes, five classes, three rules. A classification is displayed only where the scan earns it.
Every grade here is assigned by the same rules on every scan, and the methodology page renders those rules from the code that enforces them.