Like the deployment checklist T411065, but in reverse.

Reason
Archiving the WP25EasterEggs extension following the end of the Wikipedia 25th anniversary celebration.

Undeployment Checklist

This Task

• Add maintainers of WP25EasterEggs as subscribers to this task (if they have no apparent Phabricator account, notify them on-wiki or via email if possible and note it here).
• Add Phabricator project MediaWiki-extensions-WP25EasterEggs as a tag for this task

On-Wiki Documentation

• Archive extension page https://www.mediawiki.org/wiki/Extension:WP25EasterEggs: replace page contents with {{Archived extension|last revision id before archiving|task=T######}}.
• If documentation page was translatable, remove <translate>, visit Special:PageTranslation, and click "remove from translation" (if you don't have the translation administrator right, ask a user who does).
• Archive the help page https://www.mediawiki.org/wiki/Help:Extension:WP25EasterEggs
• WMF stewardship: Remove the project from the mediawiki Maintainers page
• Update Wikidata item associated with documentation page:
  • Add statement Abandonware (Q281039) to instance of (P31) together with qualifier start time (P580) = YYYY-MM-DD date of archival
  • Add qualifier end time (P582) = YYYY-MM-DD (same date) to instance of (P31) = MediaWiki extension (Q6805426)

Phabricator

• Mark all Phabricator tasks for the extension either Declined or Invalid. Add a comment pointing to this task when doing so for reference.
• Archive Phabricator project MediaWiki-extensions-WP25EasterEggs
• Archive Phabricator project PES1.3.3 WP25 Easter Eggs
• Edit Phabricator project descriptions with a link to this ticket.

Portal

• Remove the birthday mode features from www.wikipedia.org

Translatewiki.net / Translations

• Remove the extension completely from translatewiki.net by ensuring its project IDs don't appear in any of the following files:
  • groups/MediaWiki/ExtensionsAgg.yaml
  • groups/MediaWiki/mediawiki-extensions.txt
  • repoconfig.yaml
  • mw-config/validation-exclusion-list.php
  • Remove from WikimediaMainAgg.yaml, WikimediaAdvancedAgg.yaml, WikimediaLegacyAgg.yaml, or WikimediaTechnicalAgg.yaml as applicable.

Configuration / Tests / Integrations

• Remove tests in integration/config (zuul/layout.yaml).
• Remove manifest/other references from mediawiki/vagrant if they exist.
• Remove from https://doc.wikimedia.org/cover-extensions/ if present (requires Continuous-Integration-Infrastructure shell user to delete directly from the server).

Repositories

• Remove from mediawiki/extensions (along with in .gitmodules).
• Mark the repository read-only in Gerrit: edit description to prepend "[ARCHIVED]" and a reference to this task, remove all access lists and reparent on All-Archived-Projects: (provide Gerrit Repository URL).
• Deactivate the Diffusion repository for the extension: (provide the Diffusion repository callsign or URL).
• Delete the GitHub mirror: (provide GitHub repository URL).

Feature code

• Revert changes made in Vector to support baby globe
• Revert changes made in MobileFrontend to support baby globe