The point there is that what spectre/meltdown exploits are sideffects that are not part of the architectural state as it is specified by any manufacturer. The w

The point there is that what spectre/meltdown exploits are sideffects that are not part of the architectural state as it is specified by any manufacturer. The whole issue points to the fact that security-wise the typical approach used for descriptions of CPU's architectural behavior is insufficient as there can be implementation-specific observable sideeffects that have security ramifications.