Examine source code of FormFiller

{
  "description": "Auto-completing HTML forms with random data",
  "manifest_version": 2,
  "name": "FormFiller",
  "version": "1.1",
  "browser_action": {
    "default_icon": {
      "32": "icons/check.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "form-filler.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background-handler.js"
    ]
  }
}