Matching rule use definitions map certain attribute types with a matching rule definition for extensible match filters.
Extensible match filters allow clients to search using distinguished name (DN) components,
such as (
ou:dn:=engineering), or using an OID number, such as
cn:126.96.36.199:=Sam Carter). The matching rule use attribute publishes
those attribute types and matching rule combinations, which can be used in extensible match
Typically, you define a matching rule use that isn't normally specified in the attribute type definition. You can create new matching rule uses from the existing schema definitions by adding a custom schema file in the <server-root>/config/schema directory.