Examine source code of Minecraft

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Cool Minecraft Theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(27, 40, 45)",
      "toolbar_text": "rgb(140, 140, 140)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(140, 140, 140)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(140, 140, 140)",
      "tab_line": "rgb(146, 15, 15)",
      "popup": "rgb(22, 48, 57)",
      "popup_text": "rgb(211, 216, 217)",
      "button_background_hover": "rgb(101, 34, 34)",
      "tab_loading": "rgb(146, 15, 15)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f21f8fb1-8cda-4046-a10f-4e3aa1248c93}"
    }
  }
}