According to the description of https://phabricator.wikimedia.org/project/profile/85/ Diffusion-Repository-Administrators is not for requesting Gerrit repositories. Instead such requests should be made on https://www.mediawiki.org/wiki/Gerrit/New_repositories/Requests
However ironically Diffusion-Repository-Administrators has a New Gerrit repo column for years now and some requests are handled in Phabricator such as T259078.
This means there have two places instead of one to look up when someone requested some Gerrit repository when, and that is annoying.
A discussion started 29 November 2019: https://www.mediawiki.org/wiki/Topic:Uqfdno10snrrfmc0