Michael Catanzaro authored Jun 25, 2021 and Michael Catanzaro committed Jun 28, 2022

Since 6cfbb00a this setting is
supposedly unused, but in fact it has always been used. My archeology
has failed to turn up a reason for it to have been documented as unused.

I intend to remove all these settings eventually, because they are in
the wrong place, but in the meantime we might as well document them
properly.

Related: glib#2291