Expands to the value of an attribute from the current object in the current operation and in the source data store. It can be logically thought of as the union of the operation attribute token and the source attribute token. It does not include the removed values from a modify operation.
Specify the name of the attribute.
If the token is used in a context where a node set is expected, the token expands to a node set containing all of the values for that attribute. If it is used in a context where a string is expected, the token expands to the string value found.