Seven Star Stance
OP commented that he was mainly concerned with the foot position of the movement. This is "Seven Star Stance", one of the primary stances of Northern Mantis generally, although it may bear different names outside of the Seven Star Mantis style.
I tried to find better pictures, honestly. This one does not show a proper Seven Star Stance. Notice that the foot is 90 degrees out from the body. In the picture you included, notice how the back leg is bearing most of the weight, and the back foot is angled at approximately 45 degrees out from the body. That is a proper Seven Star stance.
Nonetheless, it was the only readily available photo involving another person that depicted the intent of the movement. Seven Star Stance is always a foot capture, and it usually occurs from the outside of the foot.
There are many potential applications to the foot capture. Consider the effect of the fighter in the above photo doing the following:
- grabbing the opponent's right wrist and pulling him in tight
- applying his arm against the opponent's throat
- sweeping the opponents foot forcefully
Here is a video of Wong Kiew Kit demonstrating this application at 00:30
Below is a drawing of another route you could go after capturing the foot.