Examine source code of InputOutfocus

{
  "manifest_version": 2,
  "name": "InputOutfocus",
  "version": "1.0",
  "description": "make focus out when you change windows in browser",
  "icons": {
    "64": "icons/64.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "inputoutfocus.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d014ecda-9273-47aa-a71a-12932fdc47b7}"
    }
  }
}