**BlueSpiceUserPreferences is not in use anymore and should be archived**
BlueSpiceUserPreferences relies on a deprecated function:
```
BlueSpiceUserPreferences BsConfig::getRegisteredVars was deprecated in MediaWiki 3.0.0.
[Called from UserPreferences::onUserGetDefaultOptions
in /workspace/src/extensions/BlueSpiceUserPreferences/UserPreferences.class.php at line 213]
```
**To-Do list**
- [x] Add maintainers of that extension as subscribers to this task
- [ ] Archive documentation on `mediawiki.org` (https://www.mediawiki.org/wiki/Extension:UserPreferences maybe?)
- [ ] Archive Wikidata item associated with mediawiki.org documentation page (remove nearly all statements, except `instance of (P31) = MediaWiki extension (Q6805426)`, which should add a qualifier `end time (P582) = the YYYY-MM-DD date that you decided to archive extension, generally per edit history`, change English (and other languages if possible) description to "archived MediaWiki extension" (and its translation))
- [ ] ~~Remove from `mediawiki/extensions`/`mediawiki/skins` (along with in `.gitmodules`).~~ Kept until the release branches are no longer needed
- [ ] ~~Remove tests in `integration/config` (`zuul/layout.yaml` ).~~ Kept until the release branches are no longer needed
- [x] Remove from `translatewiki.net` (`groups/MediaWiki/mediawiki-extensions.txt`/`groups/MediaWiki/mediawiki-skins.txt`).
- [] ~~Remove manifest/other references from `mediawiki/vagrant` if they exist.~~
- [x] Empty repository and add an README file.
- [] Remove from https://doc.wikimedia.org/cover-extensions/ if present (requires #continuous-integration-infrastructure shell user to delete directly from the server)
- [ ] Archive Phabricator project <#ProjectX> for associated extension/skin, and mark all tasks of that project either Declined or Invalid.
- [ ] Edit Phabricator project <#ProjectX> description for associated extension/skin with a link to this ticket.
- [ ] Archive the extension's diffusion repository: (provide the Diffusion repository callsign or URL).
- [ ] Mark the repository read-only in Gerrit: (provide Gerrit Repository URL).
- [ ] Delete the GitHub mirror: (provide GitHub repository URL).