I would think that it indicates the direction of a read for the variant, i.e. there may be 49 C's found on reads aligning to the forward strand and 99 from reads aligning to the reverse strand. You can manually check that by right clicking on the alignment track --> "color by" --> "strand" and just check, e.g. for the T's whether that would explain those numbers.
+
number of reads mapped to the plus strand-
number of reads mapped to the minus strandThank you!