Examine source code of Potok Extension

{
  "name": "Potok.io Extension",
  "description": "Hiring without headache",
  "version": "4.6.2",
  "homepage_url": "https://potok.io/",
  "minimum_chrome_version": "45",
  "short_name": "potok.io Ex",
  "background": {
    "scripts": [
      "extension.js"
    ]
  },
  "browser_action": {
    "default_icon": "assets/icon16.png",
    "default_title": "Potok.io",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "cookies",
    "*://*.superjob.ru/*",
    "*://*.potok.io/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.hh.ru/*",
        "*://*.hh.ua/*",
        "*://*.grc.ua/*",
        "*://*.hh.kz/*",
        "*://*.hh.uz/*",
        "*://*.rabota.by/*",
        "*://*.career.ru/*",
        "*://*.github.com/*",
        "*://*.vk.com/*",
        "*://*.facebook.com/*",
        "*://*.linkedin.com/*",
        "*://*.linkedin.cn/*",
        "*://*.career.habr.com/*",
        "*://*.superjob.ru/*",
        "*://*.rabota.ua/*",
        "*://*.zarplata.ru/*",
        "*://*.avito.ru/*",
        "*://*.job.ru/*",
        "*://*.job-mo.ru/*",
        "*://*.joblab.ru/*",
        "*://*.vkrabota.ru/*",
        "*://*.rabota.vk.com/*",
        "*://*.rabota.ru/*",
        "*://*.farpost.ru/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "assets/icon16.png",
    "48": "assets/icon48.png",
    "128": "assets/icon128.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{2546c560-6d04-4e38-b8f0-126ae572c0b3}"
    }
  }
}