There's no reason to remove them, that's not what I'm asking. By all means leave them in, but why leave them undocumented? Explain their existence, their parame

There's no reason to remove them, that's not what I'm asking. By all means leave them in, but why leave them undocumented? Explain their existence, their parameters & capabilities. If not intended for use, explain that too. Then when something unexpected like Spectre comes along, the people that have to deal with it can say "Oh yeah, those testing instructions provide another vector of attack that our patch has to account for." Instead we're in this situation, and I'm pretty sure there's at least a half dozen nations that would have already devoted the resources needed to uncover undocumented instructions like this, meaning ample opportunity to have developed various exploits.