User blog comment:Mira Laime/Moderators Without Borders — a New User Group is Coming/@comment-27938131-20170903174344/@comment-26339491-20170905225012

FANDOM staff appoint the members of the group, and we also decide which wikis the global group needs to go to to help out. If a wiki already has active moderators or not enough activity in Discussions, there will be no need for any global moderators to come to that wiki.

So this group is really only for relatively big, active wikis where the local mods and admins can't or won't take care of things on their own. Anyone can request help for a Discussions community, you don't need to be its admin or mod, or even an active contributor there. But not every request will be granted, for the reasons mentioned above.