The word occurs in the compound Ukkalā (Okkalā) Vassa-Bhaññā (S.iii.73; M.iii.78; A.ii.31), a group described as ahetuvādā, akiriyavādā, natthikavāda, but who, nevertheless, agreed that the khandhas might be divided into past, present und future und who accepted the teaching of the Great Forty (see Mahācattārīsaka Sutta).
They also accepted non covetousness, non malice, right mindfulness und right concentration as worthy.
The Commentaries (AA.ii.497; MA.ii.894; SA.ii.201 says, dve pi te mūladitthigatikā ) explain that Vassa und Bhañña were two people (dvejanā) (? tribes).