Examine source code of YouTube Enhancer

{
  "manifest_version": 2,
  "name": "YouTube Enhancer",
  "description": "Firefox add-ons enhance your YouTube™ experience with features like ad blocking, video loading, autoplayback, playback speed adjustment, night block mode, skip intros, playlist management, Advanced search and notes.",
  "version": "1.3.1",
  "author": "Tautvydas Derzinskas",
  "homepage_url": "https://github.com/SlimDogs/make-youtube-great-again",
  "browser_action": {
    "default_icon": {
      "19": "icons/icon_19x19.png",
      "38": "icons/icon_38x38.png"
    },
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/icon_16x16.png",
    "48": "icons/icon_48x48.png",
    "96": "icons/icon_96x96.png",
    "128": "icons/icon_128x128.png"
  },
  "background": {
    "scripts": [
      "background.bundle.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "css": [],
      "js": [
        "content.bundle.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    },
    {
      "matches": [
        "*://*.flvto.biz/*"
      ],
      "include_globs": [
        "*#*"
      ],
      "js": [
        "flvto.bundle.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    },
    {
      "matches": [
        "*://*.onlinevideoconverter.com/youtube-converter*"
      ],
      "include_globs": [
        "*#*"
      ],
      "js": [
        "onlinevideoconverter.bundle.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "css/bars/*.css",
    "images/bars/*.*"
  ],
  "content_security_policy": "script-src 'self' https://ssl.google-analytics.com; object-src 'self'",
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{526c442e-a49e-4c72-9b36-9ca1a6b0e4b8}"
    }
  }
}