A specific build of an SDK (Software Development Kit) used for mobile-to-web authentication. Why "Best" Solutions Matter

Check your xfbml and version parameters in the FB.init call.

The keyword appears to be a unique technical identifier, likely an error code or a specific developer string associated with Facebook’s internal JavaScript libraries or API integrations. If you are encountering this specific string during development or browsing, it usually points to a breakdown in how a third-party application communicates with the Facebook platform.

A temporary or unique URL fragment used for data exchange.

Which or device are you using when this string appears?

Are you a trying to fix code or a user encountering this on a website?