Examine source code of Simple Sage

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Simple Sage",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-009-f069b97f439938a011297c84464f0df6.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(99, 112, 77)",
      "toolbar_text": "rgb(225, 232, 217)",
      "frame": "rgb(114, 132, 86)",
      "tab_background_text": "rgb(234, 244, 224)",
      "toolbar_field": "rgb(69, 81, 56)",
      "toolbar_field_text": "rgb(225, 232, 217)",
      "tab_line": "rgb(62, 90, 62)",
      "popup": "rgb(86, 100, 71)",
      "popup_text": "rgb(225, 232, 217)",
      "button_background_hover": "rgb(108, 125, 89)",
      "ntp_background": "rgb(216, 223, 208)",
      "tab_loading": "rgb(62, 90, 62)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b2b1b2c8-2d59-4e62-ac6b-4d121bbc31c0}"
    }
  }
}