Internal focalization
The narrative is filtered through one character's consciousness: we know only what they know, see only what they see.
In internal focalization (Genette's typology), the narrative adopts a character's point of view: the reader perceives the scene through their senses, knowledge and biases. The narrator may say "he" or "I" — the restriction is the same: no information the focal character can't access.
It's the dominant regime of the contemporary novel, because it manufactures identification: inhabiting a consciousness means adopting its cause. Its constraint is its richness — every description becomes characterization (what the character notices says who they are), and every error of perception becomes a plot tool.
Example
"She scanned the room: not one familiar face." (The reader sees only what she sees.)