ConnectApi.Extension

An extension.

Property Name	Type	Description	Available Version
`alternativeRepresentation`	`ConnectApi.Alternative`	Alternative representation of the extension.	40.0
`attachmentId`	String	Attachment ID of the extension.	41.0
`extensionId`	String	ID of the extension.	40.0
`payload`	String	Payload associated with the extension.	40.0
`payloadVersion`	String	Payload version that identifies the structure of the payload associated with the extension.	40.0

Apex Reference Guide