Indicates whether accrued interest is included or not in the value provided in UnderlyingCashSettlAmount(42054).
For cash settlement this specifies whether quotations should be obtained inclusive or not of accrued interest.
For physical settlement this specifies whether the buyer should deliver the obligation with an outstanding principal balance that includes or excludes accrued interest.

ISDA 2003 Term: Include/Exclude Accrued Interest.