I am convinced after much research into my own system and its files that Avast falsely reports “Junk Files” in order to get you to sign up for their service.
It claims I have 45 gigs of windows download files but when I look at ALL MY DRIVES there are none of these files to be found.
Unless you own a license for the Avast Cleanup Component, your assumption is probably correct.
If you don’t intend to purchase it, remove it via settings, components or, via Programs and Features.
Select Avast, select change and remove Cleanup.
You can also avoid items from being installed if you choose Customize when you install the product. (https://youtu.be/6_OC2o7nAoA)