Seems on dozens of Wikimedia wikis (except Wikipedias) and translatewiki.net.
Try "all" and "none" buttons of these:
- Wikipedia (Please Do Not directly type asdfg, it redirects to "Touch typing" article)
- Wiktionary
- Wikibooks
- Wikinews
- Wikiquote
- Wikisource
- Wikiversity
- Wikivoyage
- Meta-Wiki
- Commons
- Wikispecies
- MediaWiki.org
- Wikidata
- Outreach Wiki
- Translatewiki.net
and so on...