Examine source code of e621 Responsive Mode

{
  "manifest_version": 2,
  "name": "e621 Responsive Mode",
  "version": "1.7",
  "description": "Enhances e621 by making the site fully responsive, ensuring a better browsing experience on mobile and various screen sizes",
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "run_at": "document_idle",
      "matches": [
        "*://*.e621.net/*"
      ],
      "js": [
        "e621responsive.js"
      ]
    },
    {
      "run_at": "document_start",
      "matches": [
        "*://*.e621.net/*"
      ],
      "css": [
        "e621responsive.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f5b8719d-6d9d-4dda-8bfc-ce6b9a71f9fb}"
    }
  }
}