Yes, that's it exactly. "Mindfulness" or "meditation" or whatever you want to call it is nothing more than a set of practices that gives your conscious mind awareness of and access to processes in your brain that it doesn't by default have access to. There's nothing mysterious or woowoo about it, other than the fact that your brain is not a computer so the activity by which this access is gained looks a little weirder (to a tech person) than hooking up a connector to a BDM interface. But it amounts to (more or less) the same thing.
I think the brain may very well have some hidden parts. For example, when we dream, a different part of the brain comes up with a plot for the dream which we don't have control over. It's almost like the brain is being trained using an adversarial network.