Examine source code of flying_mouse

{
  "manifest_version": 2,
  "name": "fly",
  "version": "1.1",
  "description": "Adds a fly under the pointer.",
  "icons": {
    "64": "icons/fly.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "fly.js"
      ]
    }
  ]
}