Count of A, C, G, T bases across all samples
INFO=<ID=BaseCounts,Number=4,Type=Integer,Description="Counts of each base">
This annotation returns the counts of A, C, G, and T bases across all samples, in that order.
BaseCounts=3,0,3,0
This means the number of A bases seen is 3, the number of T bases seen is 0, the number of G bases seen is 3, and the number of T bases seen is 0.