Detectron: how to understand 'skeleton' in coco datasets keypoint?

hi!
In the coco datasets, I use keypoints, and there is "skeleton" in categories such as:

"skeleton": [
                [
                    16, 
                    14
                ], 
                [
                    14, 
                    12
                ], 
                [
                    17, 
                    15
                ], 
                [
                    15, 
                    13
                ], 
                [
                    12, 
                    13
                ], 
                [
                    6, 
                    12
                ], 
                [
                    7, 
                    13
                ], 
                [
                    6, 
                    7
                ], 
                [
                    6, 
                    8
                ], 
                [
                    7, 
                    9
                ], 
                [
                    8, 
                    10
                ], 
                [
                    9, 
                    11
                ], 
                [
                    2, 
                    3
                ], 
                [
                    1, 
                    2
                ], 
                [
                    1, 
                    3
                ], 
                [
                    2, 
                    4
                ], 
                [
                    3, 
                    5
                ], 
                [
                    4, 
                    6
                ], 
                [
                    5, 
                    7
                ]
            ]

In coco document, it declares such as:
"skeleton", which defines connectivity via a list of keypoint edge pairs and is used for visualization.
But I can't understand what it means. Can you help me please? Thanks!