Examine source code of Hallway

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Hallway",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(69, 67, 110)",
      "frame": "rgb(0, 5, 87)",
      "tab_background_text": "rgb(13, 0, 255)",
      "toolbar_field": "rgb(0, 8, 140)",
      "toolbar_field_text": "rgb(19, 22, 80)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgb(41, 42, 60)",
      "popup_text": "rgb(0, 7, 139)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0fe01f3a-5d55-47c0-bb9f-94274bfc06ac}"
    }
  }
}