2015 Document 6209 is a reference guide which contains ADP and IDRS data relative to various components of the IRS. It is updated annually.
Section 8A, Master File Codes - Transaction, MF and IDRS Collection Status, Freeze and IDRS Status 48, Restrictive and Filing Requirement
Section 8B, Master File Codes - Unpostable and Resequence
Section 8C, Master File Codes - Source, Reason, Hold, Priority, Item Adjustment & Credit Reference, NMF Abstract, Underreporter Process, No Merge Reason, EP Merge Fail Reason, TC 971 Action, Master File, and IDRS Location