The symbol frequencies counted in all proteins.

Example: Assume that you provided 2 protein sequence sets. Then this first example line means that in the first protein of the set A the amino acid Y (tyrosine) occurs with a frequency of 0.016 i.e. 1.6% of all resuides in this protein are tyrosines (5% would be expected if all amino acids would be equally used.)

DATASET AA FREQ
setA Y 0.016

Description of set A: '$SETA'
Description of set B: '$SETB'