That's true love of animals!
This protector instinct is cute. The little cat just does not want her master even holding out his hand. Way too dangerous!
This little kitten would probably do something to save his master from a tough situation. But it does not have to come that far. After all, caution is better than forbearance.
That's why the cat owner should not be in danger. For his cat, even holding his hand out of the window is far too great a risk - as this video clearly shows.
When his master holds his hand out of the window, the kitten is instantly in place and pulls the "endangered" body part back on the windowsill. Carefully, she still casts a searching glance out of the window.
Since we can probably speak of true love between cats and humans!
Further examples of the intimate love between man and animal:
Dog faints for joy
Fawn cuddles like a baby