Common schema elements must be included on all resources and are used to provide a reference identifier for the resource as well as information about the resource:

id String Unique identifier for the resource as defined by the Service Provider [REQUIRED]
externalId String Identifier for the resource as defined by the SCIM Consumer (i.e. a local identifier or customerId in an application) [REQUIRED]
meta Complex Attribute The resources metadata, the "meta" complex attribute may consist of the following attributes: [REQUIRED]
created meta DateTime When the resource was created
lastModified meta DateTime When the resource was last modified (if the resource has not been modified since creation, this value will be the same as the created attribute)
location meta String The direct URI of the resource. You can use this URI to directly manage a resource rather than searching for it and then modifying.
version meta String (if supported). The version of the resource being returned.
attributes meta String (multi-valued) (if supported). Contains the list of attributes to remove during a PATCH operation.