**Reason**
Per T334415#9353983
**To-do list**
- This task
-- [x] Add maintainers of that extension/skin 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] Add Phabricator project <#ProjectX> as a tag for this task, and remove #mediawiki-extensions-other/#other-skins as appropriate.
- On-wiki documentation
-- [x] Archive documentation on `mediawiki.org` (provide URL): https://www.mediawiki.org/wiki/Grants_Review_app (use `{{historical}}` and link to this task)
-- [ ] ~~Update Wikidata item (provide URL) associated with documentation page~~
--- [ ] ~~add statement `Abandonware (Q281039)` to `instance of (P31)` together with qualifier `start time (P580)` = the YYYY-MM-DD date that you decided to archive extension/skin (generally per edit history)~~
--- [ ] ~~add qualifier `end time (P582)` = the YYYY-MM-DD (same date as above) to `instance of (P31) = MediaWiki extension (Q6805426)/MediaWiki skin (Q21996535)`~~
- Phabricator
-- [x] Mark all Phabricator tasks for #Wikimedia-IEG-grant-review. Add a comment pointing to this task when doing so for reference.
-- [x] Archive Phabricator project #Wikimedia-IEG-grant-review
-- [x] Edit Phabricator project Wikimedia-IEG-grant-review description with a link to this ticket.
- Translatewiki.net/translations
-- [x] Remove from `translatewiki.net` ([[ https://gerrit.wikimedia.org/r/plugins/gitiles/translatewiki/+/refs/heads/master/groups/MediaWiki/mediawiki-extensions.txt | groups/MediaWiki/mediawiki-extensions.txt ]] / [[ https://gerrit.wikimedia.org/r/plugins/gitiles/translatewiki/+/refs/heads/master/groups/MediaWiki/mediawiki-skins.txt | groups/MediaWiki/mediawiki-skins.txt ]]) - see https://translatewiki.net/wiki/Translating:Wikimedia_Grants_Review
- Configuration/tests/integrations/etc.
-- [x] Remove tests in [[ https://gerrit.wikimedia.org/g/integration/config | integration/config ]] ([[ https://gerrit.wikimedia.org/r/plugins/gitiles/integration/config/+/master/zuul/layout.yaml | zuul/layout.yaml ]]).
-- [ ] ~~Remove manifest/other references from [[ https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/vagrant/+/master | 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 is archived, and referring to this task by URL.
-- [ ] Mark the repository read-only in Gerrit (also edit description to prepend "[ARCHIVED]" and a reference to this task): https://gerrit.wikimedia.org/g/wikimedia/iegreview/
-- [ ] Deactivate the Diffusion repository: rWIEG
-- [ ] Delete the GitHub mirror: https://github.com/wikimedia/wikimedia-iegreview/