Examine source code of Colnet-Average-Adder

{
  "manifest_version": 2,
  "name": "Colnet-Average-Adder",
  "short_name": "Average Adder",
  "description": "Ajoute la moyenne de la classe",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "version": "0.0.2resigned1",
  "content_scripts": [
    {
      "matches": [
        "https://enligne.cmontmorency.qc.ca/*"
      ],
      "js": [
        "jquery-3.2.1.min.js",
        "average-adder.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6909b11f-ebba-47fa-b39e-a5591e6063b3}"
    }
  }
}