It represents an error response from the server. It contains error information such as the error code, http status code, technical message, and displayable message. It's used whenever the server needs to communicate an error or failure to the client.
It's a type of integer that represents the error code:UNKNOWN_ERROR:1AUTHENTICATION_ERROR:2NETWORK_ERROR:3STORE_INSTALLATION_ERROR:4CALLER_NOT_SIGNED:5UNKNOWN_SERVER_ERROR:6PERMISSIONS_FAILURE:7
Human readable description of the error that can be displayed to the user. Might be the empty string if there is no user-appropriate description available. Not intended to be parsed as it might change at any time or be translated.