**Reason**:
- Obsolete (requires LQT), and has security flaws. Only one wiki using it in WikiApiary, and that wiki is on 1.16.x, so it wouldn't even affect them anyways.
- [x] Archive documentation on `mediawiki.org` (https://www.mediawiki.org/wiki/Extension:Reflect).
- [ ] Remove from `mediawiki/extensions` / `mediawiki/skins` (along with in `.gitmodules`).
- [ ] Remove tests in `integration/config` (`zuul/layout.yaml`).
- [ ] Remove from `translatewiki` (`groups/MediaWiki/mediawiki-extensions.txt` / `groups/MediaWiki/mediawiki-skins.txt`).
- [ ] Remove manifest/other references from `mediawiki/vagrant` if they exist.
- [ ] Empty repository and add an ARCHIVED file.
- [ ] Remove from https://doc.wikimedia.org/cover-extensions/ if present (requires #continuous-integration-infrastructure shell user to delete directly from the server)
- [ ] Archive the extension's diffusion repository: (https://phabricator.wikimedia.org/diffusion/EREF/).
- [ ] Mark the repository read-only in Gerrit: (https://gerrit.wikimedia.org/g/mediawiki/extensions/Reflect).
- [ ] Delete the GitHub mirror: (https://github.com/wikimedia/mediawiki-extensions-Reflect).