Examine source code of YouTube Timestamps

{
  "manifest_version": 2,
  "name": "YouTube Timestamps",
  "version": "1.6.0",
  "description": "YouTube timestamps made easy",
  "icons": {
    "48": "assets/icon.png"
  },
  "content_scripts": [
    {
      "js": [
        "assets/browser-polyfill.js",
        "assets/index-42532d0e.js"
      ],
      "matches": [
        "*://*.youtube.com/*"
      ]
    }
  ],
  "permissions": [
    "storage",
    "activeTab"
  ],
  "web_accessible_resources": [
    "injected.js",
    "messages-1b86fb2c.js",
    "player-904fdc91.js",
    "dom-49654c8b.js",
    "content_scripts/index.js"
  ],
  "browser_action": {
    "default_icon": {
      "128": "assets/icon.png"
    },
    "default_title": "YouTube Timestamps",
    "default_popup": "popup/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{012ec381-447c-4a32-b906-1ed0bb1dd61c}"
    }
  }
}