Examine source code of Oodi Average

{
  "manifest_version": 2,
  "name": "Oodi Average",
  "version": "0.2resigned1",
  "permissions": [
    "https://oodi.aalto.fi/a/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://oodi.aalto.fi/a/omatopinn.jsp?*"
      ],
      "js": [
        "average.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f9111709-8e12-4fba-9bf0-8e91ad235e81}"
    }
  }
}