OpenCV/opencv_contrib/modules/aruco/samples/tutorial_camera_params.yml

%YAML:1.0
camera_matrix: !!opencv-matrix
   rows: 3
   cols: 3
   dt: d
   data: [ 628.158, 0., 324.099,
       0., 628.156, 260.908,
       0., 0., 1. ]
distortion_coefficients: !!opencv-matrix
   rows: 5
   cols: 1
   dt: d
   data: [ 0.0995485, -0.206384,
       0.00754589, 0.00336531, 0 ]