Examine source code of WolnaDzida v2

{
  "manifest_version": 2,
  "name": "WolnaDzida v2",
  "version": "1.2",
  "author": "Zbyszggo",
  "description": "Allow to remove posts from authors you don't want to see. Better, faster and smoother than version 1",
  "content_scripts": [
    {
      "matches": [
        "*://*.jbzd.com.pl/mikroblog*"
      ],
      "js": [
        "jquery.js",
        "js-cookie.js",
        "users_black_list.js"
      ]
    }
  ],
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": {
      "48": "icon.png"
    }
  },
  "permissions": [
    "tabs",
    "<all_urls>"
  ]
}