If you look closely, you can see the springy retention clips in the plug. Below is a Stack Overflow answer with more details, it includes a link to the USB-C spec where you can also see the corresponding notches in the male part of the receptacle.
https://superuser.com/questions/1577898/how-does-the-retaini...
Also, some good USB-C cables have a very similar click to Lightning, including Apple's own USB-C cables. Lightning and USB-C are essentially the same design, except USB-C adds an automotive-style shroud around the male side.