Examine source code of Twitch Sound Notification

{
  "manifest_version": 2,
  "name": "Twitch Sound Notification",
  "version": "2.0",
  "description": "Twitch Sound Notification",
  "default_locale": "ru_RU",
  "icons": {
    "96": "icons/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "TwitchSoundNotification@SneiroGames.ru",
      "strict_min_version": "80.0"
    }
  },
  "permissions": [
    "<all_urls>",
    "tabs",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.twitch.tv/*"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/icon.png",
    "default_title": "Twitch Sound Notification",
    "default_popup": "popup/popup.html"
  }
}