Without this, apt would try and download way too many indices, resulting
in 128 “Ign:” lines. With this, we're down to 4 “Ign:” lines (Release.gpg
and InRelease, twice).
Funnily enough, that changes apt's behaviour, which suddenly requires
uncompressed Packages to be present.
Some gzip calls have --no-name, which disables both the original name
and timestamp; use -n (disables original name) and -m (disables original
timestamp) for pigz, for all calls.