.PAK files.
I would be very hesitant to dl a .pak file without a way like arc's v option to
check needed disk space and prevent filename conflicts. I would also worry
about potential trojan horses being upload with an innocent looking .pak
extension. One of the beauties of arc is that I know I'm not going to trash a
disk by just un-arcing the files. I can then write-protect my disks before I
run an unknown commodity.