Ævar Arnfjörð Bjarmason [off-list ref] writes:

The only in-tree user has been this test added in
3ad0401e9e6 (submodule update: silence underlying merge/rebase with
"--quiet", 2020-09-30), it wasn't per-se testing --quiet, but fixing a
bug in e84c3cf3dc3: It used to set "GIT_QUIET=0" instead of unsetting
it on "-v", and thus we'd end up passing "--quiet" to "git
submodule--helper" on "-v", since the "--quiet" option was passed sing
the ${parameter:+word} construct.

Ah, that explains why we have a test for something that seemed so
unnecessary. Note to self to dig a little more in the future.

Furthermore, even if someone had used the "-v" option they'd only be
getting the default output. Our default in both git-submodule.sh and
"git submodule--helper" has been to be "verbose", so the only way this
option could have matter is if it were used as e.g.:

    git submodule --quiet update -v [...]

I.e. to undo the effect of a previous "--quiet" on the command-line.

Signed-off-by: Glen Choo <redacted>
Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>

The additional motivation looks great, and I think it's changed
sufficiently that you should be the author instead of me.