Examine source code of Video Speed Controller - BETA Channel

{
  "name": "Video Speed Controller - BETA Channel",
  "version": "0.8.3",
  "manifest_version": 2,
  "description": "BETA testing release of Video Speed Controller. Speed up, slow down, advance and rewind HTML5 audio/video with shortcuts",
  "homepage_url": "https://chrome.google.com/webstore/detail/video-speed-controller-be/kgciknbfdanakgjeeoihchpljcejkkdj",
  "permissions": [
    "storage",
    "https://*/*"
  ],
  "browser_action": {
    "default_title": "videospeed-controller-beta",
    "default_popup": "assets/html/popup.html"
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "<all_urls>"
      ],
      "match_about_blank": true,
      "exclude_matches": [
        "https://plus.google.com/hangouts/*",
        "https://hangouts.google.com/*",
        "https://meet.google.com/*"
      ],
      "css": [
        "assets/css/content.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "16": "assets/images/icon16.png",
    "48": "assets/images/icon48.png",
    "128": "assets/images/icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "web_accessible_resources": [
    "assets/css/content.css",
    "background.js.map",
    "content.js.map",
    "options.js.map",
    "popup.js.map"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "browser@extension.com",
      "strict_min_version": "57.0"
    }
  }
}