Examine source code of Custom Image Sources

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "1.0",
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png"
  },
  "chrome_url_overrides": {
    "newtab": "tabs.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "91.1.0",
      "id": "{d50d7093-df27-4685-ab19-e428087c94c8}"
    }
  }
}