I'm thinking of the way a lot of people (myself included) remember information out of a history book: You superficially understand that the information is true, but remembering it doesn't feel like understanding an actual part of reality, it feels like retaining an abstract piece of information. Like you know it's real, but you don't feel that it's real.
I suppose it's generally the kind of extremely shallow awareness you have of something if you've been told about its existence, but haven't observed or experienced it yourself.