@Jdforrester-WMF I just updated a Debian 11 machine to Debian 12. Result: MediaWiki no longer works. Searching the web I stumbled upon https://discuss.freedombox.org/t/mediawiki-upgrade-notes-bullseye-to-bookworm/2609 and ran php update.php.

$ php update.php 
PHP Fatal error:  Uncaught Exception: Unable to open file /usr/share/mediawiki/extensions/LocalisationUpdate/extension.json: filemtime(): stat failed for /usr/share/mediawiki/extensions/LocalisationUpdate/extension.json in /usr/share/mediawiki/includes/registration/ExtensionRegistry.php:199
Stack trace:
#0 /usr/share/mediawiki/includes/GlobalFunctions.php(49): ExtensionRegistry->queue()
#1 /etc/mediawiki/LocalSettings.php(154): wfLoadExtension()
#2 /usr/share/mediawiki/includes/Setup.php(218): require_once('...')
#3 /usr/share/mediawiki/maintenance/doMaintenance.php(83): require_once('...')
#4 /usr/share/mediawiki/maintenance/update.php(319): require_once('...')
#5 {main}
  thrown in /usr/share/mediawiki/includes/registration/ExtensionRegistry.php on line 199

How to resolve this?
Open your LocalSettings.php and delete this line:

wfLoadExtension( 'LocalisationUpdate' );

Now run update.php. This resolved the issue for me and the wiki is loading once more.

Complete.

Mentioned in SAL (#wikimedia-releng) [2024-01-18T17:23:23Z] <James_F> Zuul: [mediawiki/extensions/LocalisationUpdate] Archive for T309694

Mentioned in SAL (#wikimedia-releng) [2024-01-18T17:23:00Z] <James_F> jforrester@doc1003:/srv/doc/cover-extensions$ sudo -u doc-uploader rm -rf /srv/doc/cover-extensions/LocalisationUpdate/ # T309694

Change 991620 merged by jenkins-bot:

[integration/config@master] Zuul: [mediawiki/extensions/LocalisationUpdate] Archive

https://gerrit.wikimedia.org/r/991620

Change 991620 had a related patch set uploaded (by Jforrester; author: Jforrester):

[integration/config@master] Zuul: [mediawiki/extensions/LocalisationUpdate] Archive

https://gerrit.wikimedia.org/r/991620

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

The LocalisationUpdate extensions has been archived. See T309694 for details.

Change 991568 merged by Zabe:

[mediawiki/extensions@master] Remove LocalisationUpdate

https://gerrit.wikimedia.org/r/991568

Change 991568 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions@master] Remove LocalisationUpdate

https://gerrit.wikimedia.org/r/991568

Change 991451 merged by Zabe:

[mediawiki/extensions/LocalisationUpdate@master] Archive repository

https://gerrit.wikimedia.org/r/991451

Change 991451 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/extensions/LocalisationUpdate@master] Archive repository

https://gerrit.wikimedia.org/r/991451

Change 697171 abandoned by Zabe:

[mediawiki/extensions/LocalisationUpdate@master] Add options to the update script of including component lists and excluding component list

Reason:

See T309694

https://gerrit.wikimedia.org/r/697171

Change 991433 merged by jenkins-bot:

[translatewiki@master] mediawiki-extensions: Remove LocalisationUpdate

https://gerrit.wikimedia.org/r/991433

Change 991447 merged by jenkins-bot:

[mediawiki/vagrant@master] Drop role::l10nupdate

https://gerrit.wikimedia.org/r/991447

Change 991447 had a related patch set uploaded (by Zabe; author: Zabe):

[mediawiki/vagrant@master] Drop role::l10nupdate

https://gerrit.wikimedia.org/r/991447

Change 991433 had a related patch set uploaded (by Zabe; author: Zabe):

[translatewiki@master] mediawiki-extensions: Remove LocalisationUpdate

https://gerrit.wikimedia.org/r/991433

Change 962188 merged by jenkins-bot:

[mediawiki/extensions/LocalisationUpdate@master] Use HookHandlers for core hooks

https://gerrit.wikimedia.org/r/962188