Examine source code of Flash Match

{
  "manifest_version": 3,
  "name": "Flash Match",
  "version": "1.0.0",
  "description": "A tiny 4x4 memory match game with glowing flip cards, score and attempt counters, and restart control.",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "64": "icons/icon64.png",
      "128": "icons/icon128.png"
    },
    "default_popup": "popup.html"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'; base-uri 'self'; connect-src 'self'; img-src 'self' data:; style-src 'self';"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "flash-match@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "strict_min_version": "142.0"
    }
  }
}