Hi Nagarjuna,
In actual fact these tables were introduced in 6.5 but if you are upgrading to 6.6 from a version prior to 6.5 you will see them introduced into the data model.
These tables are populated by the creation of Inbound Contact Rules in CI Studio for Decision Campaigns.
More information here , here and here from the online docs.
Of interest for new tables in 6.6 take a look at the new "identifiers" feature to support the Self Learner - here.
Regards
James