Examine source code of Color Picker Tool

{
  "manifest_version": 2,
  "name": "Color Picker Tool",
  "version": "1.0",
  "description": "Pick any color from the current web page.",
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2b961a46-ed0f-4afb-bad9-b5d88d483983}"
    }
  }
}