Examine source code of Average

{
  "manifest_version": 2,
  "name": "Average",
  "version": "1.1resigned1",
  "description": "Dodaje srednią do dzienniczka.",
  "content_scripts": [
    {
      "matches": [
        "*://uonetplus-opiekun.vulcan.net.pl/*"
      ],
      "js": [
        "Average.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{cb548ecd-1abb-42dc-a647-c70d4df60fce}"
    }
  }
}