These statistics track the occurrence of combinations of sum root values and low/high numbers.
The sum of ticket numbers 1-2-3-4-5-6 is 27. Sum root value is then 2+7=9. All the numbers are low. So the Sum Root + Low/High column in e.g. Package Properties window shows value 7 - 6:0 for this ticket.
The latest winning numbers in Expert Lotto 6/49 Demo Lottery are 23-29-36-42-44-47-. The sum of these numbers is 221 therefore the sum root value is 2+2+1 = 5. One number is low (23) and five numbers are high. So the Sum Root + Low/High column in e.g. Winning Numbers Properties window shows value 5 - 1:5 for this draw.
These statistics are available in summary form and also as per-ticket properties.
See also Combined Statistics and Sum Root and Low/High ticket filters.