Examine source code of Discord Notebook

{
  "name": "Discord Notebook",
  "short_name": "Discord Notebook",
  "version": "0.0.28",
  "author": "Asaf Aviv",
  "description": "Save Discord messages and view them later",
  "manifest_version": 2,
  "icons": {
    "128": "images/book.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://discord.com/*"
      ],
      "js": [
        "scripts/content.js"
      ],
      "css": [
        "styles/styles.css"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "activeTab",
    "downloads",
    "storage"
  ],
  "browser_action": {
    "default_icon": {
      "128": "images/book.png"
    }
  },
  "web_accessible_resources": [
    "scripts/inject.js"
  ],
  "background": {
    "scripts": [
      "scripts/background.js"
    ],
    "persistent": false
  },
  "content_security_policy": "script-src 'self' https://w.soundcloud.com/ https://www.youtube.com/ https://platform.twitter.com/; object-src 'self'; child-src https://w.soundcloud.com/ https://www.youtube.com/ https://platform.twitter.com/",
  "browser_specific_settings": {
    "gecko": {
      "id": "{3fa832ad-ece5-4b36-b4db-411fb4aa7afe}"
    }
  }
}