system
10
Bri,
As igor so elegantly explained, these files are not included to prevent possible false positives and conflict with the Avast scanner result.
I refer to these files as “inprocess” which means that since they are constantly changing, Avast could see them as virii and block vital system access.
In the long run, I have learned after years of testing and evaluating software…TO LEAVE WELL ENOUGH ALONE!. 
Technical: If you have time, try deleting them and see how the sytem reacts.
Good luck,
Nice meeting you Bri
Techie