Those are 100% spring terminals as the other person mentioned. I use these in my designs, you'll need to press the orange buttons quite hard as they're meant to work even in rocketry applications where bolted electrical connections may loosen.
When you press the button, you'll still need to apply mild insertion force. These work either with solid core wire, or stranded if the stranded wire has a ferrule crimped on.
Shows how pressing the button bends a metal tang away from where the wire comes in, the little area with a squiggle.