Examine source code of Coords

{
  "manifest_version": 2,
  "name": "Coords",
  "version": "0.9.6",
  "description": "Coords helps you finding out the mouse coordinates, draw points/shapes and measure width and height of anything and on the screen.",
  "icons": {
    "16": "icons/coords-16.png",
    "32": "icons/coords-32.png",
    "48": "icons/coords-48.png",
    "64": "icons/coords-64.png",
    "96": "icons/coords-96.png",
    "128": "icons/coords-128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "lib/browser-polyfill.min.js",
      "coords.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/coords-16.png",
      "32": "icons/coords-32.png",
      "64": "icons/coords-64.png"
    },
    "default_title": "Coords"
  }
}