Examine source code of Writer2x

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Writer",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(242, 237, 231)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(128, 97, 65)",
      "tab_background_text": "rgb(53, 53, 53)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(113, 64, 13)",
      "popup": "rgb(249, 241, 222)",
      "popup_text": "rgb(68, 68, 68)",
      "tab_loading": "rgb(113, 64, 13)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cd21bb2d-5f31-4e31-a471-a6658a7725d3}"
    }
  }
}