Change 725015 had a related patch set uploaded (by Bartosz Dziewoński; author: Bartosz Dziewoński):

[operations/mediawiki-config@master] Change wgExtraSignatureNamespaces to not include NS_MAIN on most wikis

https://gerrit.wikimedia.org/r/725015

(Copying my explanation from the Gerrit commit message, for the benefit of Phabricator readers)

In 2014, commit 6c6cbb0b9 added NS_MAIN to wgExtraSignatureNamespaces on all wikis in the 'special' dblist, stating that they "often have discussions, including their "village pump" equivalent, in ns 0".

That wasn't entirely true: the 'special' dblist includes a lot of wikis that don't behave that way, including major projects like Wikimedia Commons and MediaWiki.org. However, it wasn't a problem, because that config option was only used to add an extra button on the editing toolbars. Until…

Recently, we used it in the DiscussionTools extension as a proxy for guessing whether a namespace should use discussion-related features, and it turned out that actually, the main namespace on many of these wikis should not.

After this change, only the following 'special' wikis keep the config:

• incubatorwiki
• labswiki
• labtestwiki
• mediawikiwiki (edit: see T291630#7425413)
• metawiki
• outreachwiki
• wikimaniawiki
• all old Wikimania wikis
• all private wikis – also, some private wikis gain the config

It is removed from the following 'special' wikis:

• (real projects)
  • commonswiki
  • mediawikiwiki (edit: see T291630#7425413)
  • sourceswiki
  • specieswiki
  • testcommonswiki
  • testwikidatawiki
  • wikidatawiki
• (weird wikis)
  • apiportalwiki
  • donatewiki
  • foundationwiki
  • loginwiki
  • thankyouwiki
  • votewiki
• (closed wikis)
  • advisorywiki
  • nostalgiawiki
  • qualitywiki
  • strategywiki
  • usabilitywiki

Scheduled: https://wikitech.wikimedia.org/wiki/Deployments#deploycal-item-20211004T1800

@Urbanecm says it's worth announcing ahead of time. (Although I think it's a low-impact change and didn't need announcements or discussion.) I will post some notes about it on the affected wikis, and reschedule the deployment.

I posted messages at all affected projects:

• https://commons.wikimedia.org/wiki/Commons:Village_pump/Technical#Remove_main_namespace_from_wgExtraSignatureNamespaces
• https://www.mediawiki.org/wiki/Topic:Whsnekqdoly44tjq
• https://wikisource.org/wiki/Wikisource:Scriptorium#Remove_main_namespace_from_wgExtraSignatureNamespaces
• https://species.wikimedia.org/wiki/Wikispecies:Village_Pump#Remove_main_namespace_from_wgExtraSignatureNamespaces
• https://www.wikidata.org/wiki/Wikidata:Project_chat#Remove_main_namespace_from_wgExtraSignatureNamespaces

So far the only responses have been positive. I'm planning to deploy the change early next week.

Change 725015 merged by jenkins-bot:

[operations/mediawiki-config@master] Remove NS_MAIN from wgExtraSignatureNamespaces on most 'special' wikis

https://gerrit.wikimedia.org/r/725015

Mentioned in SAL (#wikimedia-operations) [2021-10-12T11:32:06Z] <urbanecm@deploy1002> Synchronized wmf-config/InitialiseSettings.php: 860ea0944d6dc1e6b5061eb84eec378eb5ac8441: Remove NS_MAIN from wgExtraSignatureNamespaces on most special wikis (T291630) (duration: 00m 57s)

The change has been applied now.

I will undo the change for MediaWiki.org, as I learned that @kostajh and the Growth team were using the signature tool in VisualEditor there: https://wikimedia.slack.com/archives/C010F7PJRRV/p1634111217031400

(Applying it to MediaWiki.org was originally inspired by @Krinkle's comment T291833#7386113)

In the long term, we'll need a more reliable way to tell whether a page is a discussion page or not, that doesn't depend on namespaces and $wgExtraSignatureNamespaces. There is some discussion on that in T249293 and T251653, and we'll need to revive that as we work on more changes to discussion pages…

Change 730598 had a related patch set uploaded (by Bartosz Dziewoński; author: Bartosz Dziewoński):

[operations/mediawiki-config@master] Add NS_MAIN back to wgExtraSignatureNamespaces for mediawikiwiki

https://gerrit.wikimedia.org/r/730598

Can't the Growth team move their signed updates page to a signed namespace instead of making the rest of us deal with it? :-)

Probably, but adding the configuration back shouldn't cause any problems, and there isn't a good reason here to make anyone change their workflow.

Change 730598 merged by jenkins-bot:

[operations/mediawiki-config@master] Add NS_MAIN back to wgExtraSignatureNamespaces for mediawikiwiki

https://gerrit.wikimedia.org/r/730598

Mentioned in SAL (#wikimedia-operations) [2021-10-13T18:14:59Z] <urbanecm@deploy1002> Synchronized wmf-config/InitialiseSettings.php: 224e2a374b1cc6327e9d8c2bca576091ce4efc74: Add NS_MAIN back to wgExtraSignatureNamespaces for mediawikiwiki (T291630) (duration: 01m 05s)