Examine source code of RKN Alert

{
  "manifest_version": 2,
  "name": "RKN Alert",
  "short_name": "RKN Alert",
  "description": "Показывает цветом иконки, внесён ли сайт в реестр Роскомнадзора.",
  "version": "0.18.9",
  "icons": {
    "16": "images/logo_16.png",
    "32": "images/logo_32.png",
    "48": "images/logo_48.png"
  },
  "permissions": [
    "webRequest",
    "<all_urls>",
    "tabs"
  ],
  "content_scripts": [
    {
      "js": [
        "check.js"
      ],
      "matches": [
        "<all_urls>"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "init.js",
      "lib/punycode.js",
      "lib/is_site_online.js",
      "lib/dns.js",
      "lib/domains.js",
      "lib/icon.js",
      "lib/indexed_db.js",
      "lib/get_ip.js",
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": true,
    "chrome_style": true,
    "page": "options/options.html"
  },
  "browser_action": {
    "default_icon": {
      "16": "images/logo_16.png",
      "32": "images/logo_32.png",
      "48": "images/logo_48.png"
    },
    "default_title": "RKN Alert",
    "default_popup": "popup/popup.html"
  }
}