The VARIATION clause, which need not be present, is repeatedly used to name each object or notification which the agent implements in some variant or refined fashion with respect to the correspondent invocation of the OBJECT-TYPE or NOTIFICATION-TYPE macro.
Note that the variation concept is meant for generic implementation restrictions, e.g., if the variation for an object depends on the values of other objects, then this should be noted in the appropriate DESCRIPTION clause.
By definition, each object specified in a VARIATION clause follows a SUPPORTS clause which names the information module in which that object is defined. Therefore, the use of an IMPORTS statement, to specify from where such objects are imported, is redundant and is not required in an information module.