Examine source code of shortcutForPH

{
  "manifest_version": 2,
  "name": "shortcutForPH",
  "version": "0.0.0.1",
  "description": "a = special,\n b = dark theme,\n space bar = play/pause,\n s = speed 2x,\n n = next,\n p = previous,\n right arrow = forward 15sec.\n\n See https://github.com/Abdify/extension_shortcutForPH",
  "homepage_url": "https://github.com/Abdify/extension_shortcutForPH",
  "icons": {
    "48": "icon1.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.programming-hero.com/*"
      ],
      "js": [
        "shortcut.js"
      ]
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icon1.png",
    "default_title": "shortcutForPH",
    "default_popup": "https://github.com/Abdify/extension_shortcutForPH"
  }
}