**Reason**
Extension unmaintained for years which will be taken over and further developed on [[ https://github.com/SemanticMediaWiki/SemanticTasks | GitHub ]].
**To-do list**
- This task
-- [ ] Add maintainers of that extension 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).
-- [x] Clone the existing repo into the new repo
- Phabricator
-- [ ] Archive Phabricator project <#ProjectX> for the extension.
-- [ ] Mark all Phabricator tasks for the extension either Declined or Invalid.
-- [ ] Edit Phabricator project <#ProjectX> description for the extension/skin with a link to this ticket.
- Translatewiki.net/translations
-- [ ] Remove from `translatewiki.net` (`groups/MediaWiki/mediawiki-extensions.txt` / `groups/MediaWiki/mediawiki-skins.txt`) (add #translatewiki.net project as a tag for this task).
- Configuration/tests/integrations/etc.
-- [ ] Remove from `mediawiki/extensions` / `mediawiki` (along with in `.gitmodules`).
-- [ ] Remove tests in [[ https://gerrit.wikimedia.org/g/integration/config | `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
-- [ ] Empty repository leaving only the README indicating the repo has moved to the new repo and referring to this task by URL.
-- [ ] Mark the repository read-only in Gerrit (Edit description to prepend "[MOVED]" and append Task reference): (provide Gerrit Repository URL).
-- [ ] Archive the diffusion repository for the extension/skin: (provide the Diffusion repository callsign or URL).
-- [ ] Delete the GitHub mirror: (provide GitHub repository URL).