Not scaled:
{
  "layers": [
    {
      "name": "Scrolling Contents Layer",
      "bounds": [4008, 4016],
      "contentsOpaque": true,
      "backgroundColor": "#FFFFFF",
      "transform": 1
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 2
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 3
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 4
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 5
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 1
    },
    {
      "name": "Horizontal Scrollbar Layer",
      "position": [0, 600],
      "bounds": [800, 0]
    },
    {
      "name": "Vertical Scrollbar Layer",
      "position": [800, 0],
      "bounds": [0, 600]
    }
  ],
  "transforms": [
    {
      "id": 1,
      "transform": [
        [0.5, 0, 0, 0],
        [0, 0.5, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1]
      ],
      "origin": [0, 0],
      "flattenInheritedTransform": false
    },
    {
      "id": 2,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, -100, 0, 1]
      ]
    },
    {
      "id": 3,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, 1008, 0, 1]
      ]
    },
    {
      "id": 4,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [1000, 0, 0, 1]
      ]
    },
    {
      "id": 5,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [600, 0, 0, 1]
      ]
    }
  ]
}

Scale=0.5:
{
  "layers": [
    {
      "name": "Scrolling Contents Layer",
      "bounds": [4008, 4016],
      "contentsOpaque": true,
      "backgroundColor": "#FFFFFF",
      "transform": 1
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 2
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 3
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 4
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 5
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 1
    },
    {
      "name": "Horizontal Scrollbar Layer",
      "position": [0, 600],
      "bounds": [800, 0]
    },
    {
      "name": "Vertical Scrollbar Layer",
      "position": [800, 0],
      "bounds": [0, 600]
    }
  ],
  "transforms": [
    {
      "id": 1,
      "transform": [
        [0.5, 0, 0, 0],
        [0, 0.5, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1]
      ],
      "origin": [0, 0],
      "flattenInheritedTransform": false
    },
    {
      "id": 2,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, -100, 0, 1]
      ]
    },
    {
      "id": 3,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, 1008, 0, 1]
      ]
    },
    {
      "id": 4,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [1000, 0, 0, 1]
      ]
    },
    {
      "id": 5,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [600, 0, 0, 1]
      ]
    }
  ]
}

Scale=1.5:
{
  "layers": [
    {
      "name": "Scrolling Contents Layer",
      "bounds": [4008, 4016],
      "contentsOpaque": true,
      "backgroundColor": "#FFFFFF",
      "transform": 1
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 2
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 3
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 4
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 5
    },
    {
      "name": "LayoutBlockFlow (positioned) DIV class='fixed'",
      "bounds": [10, 10],
      "contentsOpaque": true,
      "backgroundColor": "#C0C0C0",
      "transform": 1
    },
    {
      "name": "Horizontal Scrollbar Layer",
      "position": [0, 600],
      "bounds": [800, 0]
    },
    {
      "name": "Vertical Scrollbar Layer",
      "position": [800, 0],
      "bounds": [0, 600]
    }
  ],
  "transforms": [
    {
      "id": 1,
      "transform": [
        [1.5, 0, 0, 0],
        [0, 1.5, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1]
      ],
      "origin": [0, 0],
      "flattenInheritedTransform": false
    },
    {
      "id": 2,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, -100, 0, 1]
      ]
    },
    {
      "id": 3,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [8, 1008, 0, 1]
      ]
    },
    {
      "id": 4,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [1000, 0, 0, 1]
      ]
    },
    {
      "id": 5,
      "parent": 1,
      "transform": [
        [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [600, 0, 0, 1]
      ]
    }
  ]
}