Examine source code of YouTube Layout Tweak

{
  "description": "Improves YouTube homepage layout to be more desktop friendly with increased amount of videos per row.",
  "manifest_version": 2,
  "name": "YouTube Layout Tweak",
  "author": "Zbigniew Bogacz",
  "version": "0.9.0",
  "icons": {
    "32": "icons/yt-layout-tweak-32.png",
    "48": "icons/yt-layout-tweak-48.png",
    "96": "icons/yt-layout-tweak-96.png"
  },
  "permissions": [
    "storage"
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/yt-layout-tweak-16.png",
      "19": "icons/yt-layout-tweak-19.png",
      "32": "icons/yt-layout-tweak-32.png",
      "38": "icons/yt-layout-tweak-38.png"
    },
    "default_title": "YouTube Layout Tweak",
    "default_popup": "options_popup.html",
    "show_matches": [
      "*://*.youtube.com/*"
    ]
  },
  "options_ui": {
    "page": "options.html",
    "chrome_style": true
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "yt-tweak.js"
      ],
      "css": [
        "yt-tweak.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}