The fact is that the cat has special temporal glands near the corners of the eyes and around the nose. They keep a special secret that the animal uses to mark its territory.
The moments when the cat rubs its muzzle against the face of the owner speak of tenderness, the cat expresses not only devotion, but also love and trust in his person. Usually at such moments, the animal craves eye contact, so it chooses the face as the object for marking. The behavior of cats is mysterious and in many ways inexplicable, but the answer to the question of why cats rub their faces against the legs and face of the owner is quite simple.