The known vulnerabilities of a tank (e.g. X% will be defeated by weapon Y in situation Z) will usually be classified higher than the operator manual (which however may contain technical or tactical work-arounds). E.g. the existence of a defensive aid suite on a tank system may be unclassified (because it is plainly visible in photographs), what it does may be restricted, how it does it may be secret and how well it does it may be top secret.