from man :

--verify

Assume that the first argument is a signed file or a detached signature and

verify it without generating any output.

but it makes output (and can't be suppressed with --quiet) :

gpg --quiet --verify stage3-amd64-systemd-20160823.tar.bz2.DIGESTS.asc

gpg: Signature made Thu 25 Aug 2016 03:35:02 PM CEST using RSA key ID 2D182910
gpg: Good signature from "Gentoo Linux Release Engineering (Automated Weekly
Release Key) <releng@gentoo.org>" [ultimate]