Why Do Stray Cats Give Their Kittens to Humans?

I recently saw some videos where a stray cat gives her kitten to a human who often feeds her. It’s not just a temporary gesture, she leaves the kitten with the human and doesn’t come back for it. What do you think this behavior signifies? Is it some kind of survival instinct where the mother cat recognizes that her baby will be safer with the human? Doesn’t she miss her kitten? I’m really confused and would love to hear your thoughts.