Examine source code of Google Image Size Filter

{
  "manifest_version": 3,
  "name": "Google Image Size Filter",
  "version": "1.1",
  "description": "Adds a quick image size filter dropdown to Google Images search results.",
  "author": "Developer",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png",
    "128": "icons/icon128.png",
    "256": "icons/icon256.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.google.com/search*",
        "https://www.google.cz/search*",
        "https://www.google.co.uk/search*",
        "https://www.google.de/search*",
        "https://www.google.fr/search*",
        "https://www.google.es/search*",
        "https://www.google.it/search*",
        "https://www.google.pl/search*",
        "https://www.google.at/search*",
        "https://www.google.be/search*",
        "https://www.google.ch/search*",
        "https://www.google.nl/search*",
        "https://www.google.se/search*",
        "https://www.google.no/search*",
        "https://www.google.dk/search*"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "google-image-filter@example.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}