I guess only OP could tell us if they sounds like what they were talking about but I don’t think that would be it either. That appears to be a device for theatre, which solves the problem of revealing characters’ thoughts when the medium would make that otherwise difficult because of the absence of a narrator. In theatre (or film or other visual mediums), a narrator is optional and if a playwright doesn’t opt to use one then it can create a problem that an aside can fix, but in literature a narrator is a prerequisite and so the problem isn’t there for an aside to fix and characters’ thoughts can be transmitted through narration freely if the author chooses and there isn’t a need for an acknowledgement of the reader in doing so.