Face Mesh draws a live wireframe mask over your face, locked to it as you move.
It uses MediaPipe's FaceLandmarker, tracking one face. The model predicts hundreds of 3D landmark points across the whole face. Those points are joined into a tessellation, with the eyes and lips picked out in brighter lines. Everything runs in your browser.
Tracking is smooth in good light and falters when your face is turned well away from the camera.