Examine source code of Twitch Tools

{
  "manifest_version": 2,
  "version": "1.0.2",
  "browser_action": {
    "default_icon": {
      "28": "icons/twitch-48x48.png"
    },
    "default_title": "Twitch Tools",
    "default_popup": "popup/menu.html"
  },
  "name": "Twitch Tools",
  "description": "Move twitch chat to the left side",
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.twitch.tv/*"
      ],
      "js": [
        "content/content.js"
      ]
    }
  ],
  "icons": {
    "28": "icons/twitch-48x48.png",
    "112": "icons/twitch-128x128.png"
  },
  "web_accessible_resources": [
    "plugins/*",
    "lib/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{63e518a0-cf28-44d2-a3ef-ab9f974bc4f5}"
    }
  }
}