When you have your Web-Browser Sandboxed, all downloads will go into the default download folder, BUT they will be sandboxed. You can then run the program, without it touching system. And if its virus, it can just sit on the download folder SANDBOXED 24/7
I saw: “Site Blocking.” So, everytime a user post in a LINK to be blocked, it sends the URL/LINK to the AVAST! experts to check out the SITES so they can decide wether its Malicous or not.