Examine source code of Occicom Compagnon

{
  "manifest_version": 2,
  "name": "Occicom Compagnon",
  "version": "2.2.1",
  "browser_action": {
    "default_icon": "img/favicon.png",
    "default_title": "Occicom CTC",
    "default_popup": "index.html"
  },
  "description": "Utiliser les numéros de téléphone présentés sur une page web pour passer un appel en click to call.",
  "icons": {
    "16": "img/favicon.png",
    "48": "img/favicon.png",
    "128": "img/favicon.png"
  },
  "author": "Occicom",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "run_at": "document_end",
      "js": [
        "openDialog.js",
        "swal.js"
      ]
    }
  ],
  "permissions": [
    "https://extranet.occicom.fr/*",
    "ws://chat.compagnon.staging.k2project.fr/*",
    "http://chat.compagnon.staging.k2project.fr/*",
    "contextMenus",
    "storage"
  ]
}