Avast - Exception File Seems Odd

[thisstinks]

I am using Avast Free 7.0.1466

My PC has begun to act a little strange but Avast, Malwarebytes from safe mode and Kaspersky AVPTool found nothing, so I started poking around in the Avast expert settings and I hope someone can let me know if these are normal.

?:\PageFile.sys
*\System.da?
*\User.da?
*.fon*
*.txt
*.log
*.ini
*\Bootstat.dat
*\firefox\profiles\*sessionstore*.js

I especially find the last three to be intuitively wrong,  why skip an ini file and there is no firefox or java on this machine so why the last entry appears is befuddling

[igor]

That's the default set; it's not modified according to whether Firefox is installed or not.
As for why skip some of the filetypes - those may be files often written to (or read from), and scanning them each time could slow down the system severely.