Examine source code of SpotDiff

{
  "manifest_version": 3,
  "name": "SpotDiff",
  "version": "1.0",
  "description": "Compare two images with a before/after slider directly in the browser popup. Load from local files or URLs. Save last settings.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "permissions": [
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "spotdiff@addon",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}