If we go for the subprojects road, what about the following hierarchy?

• Wikimedia-Site-requests
  • Wikimedia-Extension-setup
  • Wiki-Setup renamed #Wikimedia-Site-Setup

If we go with subproject road, I'd suggest instead:

• Wikimedia-Site-requests (parent)
  • wikimedia-siteconfig-requests (wiki configuration changes) (note m:SITECONFIG already exists so siteconfig or siteconf won't be an uninteligible acronym nobody knows).
  • Wikimedia-Extension-setup
  • Wiki-Setup (renamed to what you propose).

Plus, if they're going to be subprojects, maybe we can just get rid of the Wikimedia prefixes?

#wikimedia-site-requests
  |
  |-- #siteconfig
  |-- #extension-setup
  |-- #site-setup

untangling subprojects is easier said than done. I recently wrote some hacky code to handle moving a subproject tree into another subproject tree but making a subproject into a standalone project is probably not feasible without just deleting it and starting over.

@mmodell So is it possible to delete Wiki-Setup and recreate it as a standalone project? Tasks can be moved to Wikimedia-Site-requests and re-tagged later with the new tag.

Collaboration-Team-Triage seems also, results new member users can't join without asking sysops

@Liuxinyu970226: Isolated and manually set parent project permissions are unrelated to the topic of this very task (subprojects and membership invocations). For your topic, please file a separate task under Collaboration-Team-Triage to revert https://phabricator.wikimedia.org/project/manage/65/#4922 and https://phabricator.wikimedia.org/project/manage/65/#10353 . There are no "sysops" involved in this at all. Thanks!

Coming here from T230194: "Wikimedia-Extension-setup" and "Wikimedia-Site-Requests" projects overlap - Archive Wikimedia-Extension-setup.
Current situation:

• Top-level parent project Wikimedia-Site-requests exists. It has one subproject called Wiki-Setup.
  • Wiki-Setup has four milestones: Delete / Redirect, Close, Rename, Create
• Top-level parent project Wikimedia-Extension-setup exists.

Questions:
Are there specific, non-theoretical reasons (e.g. your personal workflows and interests) why someone would want to keep a distinction between "change the extension setup on some wiki" versus "any other type of wiki configuration request" (and we have many types)?
Or could we archive Wikimedia-Extension-setup and use only Wikimedia-Site-requests itself?
I'd like to avoid categorization for the sake of categorization only.

/me tries to nudge this forwards, generally looks good

In T177471#6715569, @Aklapper wrote:

Are there specific, non-theoretical reasons (e.g. your personal workflows and interests) why someone would want to keep a distinction between "change the extension setup on some wiki" versus "any other type of wiki configuration request" (and we have many types)?

Getting a completely new extension deployed needs to go thru various extra steps (security/performance reviews, start branching, see also Wikimedia-extension-review-queue) but getting an already deployed extension deployed to a new site IMO does not need a separate process than a "normal" configuration change request.