Examine source code of Image Palette Extractor

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0.0",
  "description": "__MSG_extensionDescription__",
  "action": {
    "default_popup": "popup/popup.html"
  },
  "icons": {
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{216fe9ee-2df2-3896-5933-b15d580db593}",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}