Probably worth having a short description of each element in the return tuple. Maybe something like

newReadPosition - offset of the base(s) in this read's sequence that align at the specified new locus.
cigarElementLocus - ?
newIndexInCigarElements - index of the cigar element in the read that the new locus falls within.
newIndexWithinCigarElement - offset within the cigar element that the new locus falls within