@EliahKagan Oh, speaking of
muru being right most of the time, it turns out that the
apt
command
does, by default, delete
.deb
files after it installs them. I still don't know why I have cached
.deb
s but I guess they're
.deb
files that were automatically downloaded as a separate step from when I manually told
apt
to upgrade to them. Anyway I'm convinced that I was mistaken to think
apt
did not automatically delete these files.