There is a few files I added in Exclusions by clicking ‘‘Add to Exclusions’’ after I tried to open them but now I want to remove it from Eexclusions but I can’t find where all excluded files are stored 
FAQ section https://support.avast.com/support/home
Avast Antivirus: Excluding certain files or websites from scanning
https://www.avast.com/faq.php?article=AVKB168#artTitle