Examine source code of GIFit!

{
  "manifest_version": 2,
  "name": "GIFit!",
  "description": "Generate GIFs from any YouTube video with ease.",
  "version": "4.0.0",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "developer": {
    "name": "Timothy Kempf",
    "url": "https://kempf.dev"
  },
  "permissions": [
    "storage",
    "contextMenus",
    "*://*.youtube.com/*"
  ],
  "web_accessible_resources": [
    "main-world.js"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "GIFit!",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "run_at": "document_idle",
      "css": [
        "content-scripts/content.css"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{540d44b5-5810-470b-8a18-a7be59ede738}"
    }
  }
}