Specifies whether filtering is enabled for this match rule set.

If checked (selected), allows you to define a filter for this match rule set. When running a Match job, users can select the match rule set with a filter defined so that the Match job processes only the subset of records that meet the filter criteria.
If unchecked (not selected), then all records will be processed by the match rule set when the Match batch job runs.

For example, if you had an Organization base object that contained multiple types of organizations (customers, vendors, prospects, partners, and so on), you could define different match rule sets that selectively processed only the type of records you want to match: MatchAll (no filter), MatchCustomersOnly, MatchVendorsOnly, and so on.