I noticed the following Apache config in production:
<https://github.com/wikimedia/puppet/blob/7ac5f9a959924a6b51625b713e95c44ed7560ee8/modules/mediawiki/files/apache/sites/main.conf#L90>
```name=wikidata.org Apache config,lang=apache
Alias /wiki /srv/mediawiki/docroot/wikidata.org/w/index.php
Alias /ontology /srv/mediawiki/docroot/wikidata.org/w/extensions/Wikibase/docs/ontology.owl
```
This alias doesn't actually work because Wikibase isn't installed in production, instead it comes as part of Wikidata (`extensions/Wikidata/extensions/Wikibase`). This is presumably a left-over from an early beta from before that was changed.
```name=404 Not Found
https://www.wikidata.org/ontology
https://www.wikidata.org/w/extensions/Wikibase/docs/ontology.owl
```
The correct url destination would be `https://www.wikidata.org/w/extensions/Wikidata/extensions/Wikibase/docs/ontology.owl`, however that doesn't work either because `owl` is not a whitelisted file-type.
Looking further it seems that most references to this concept in XML files actually use http://wikiba.se/ontology not wikidata.org, although there are a few references to http://www.wikidata.org/ontology on the web.
* Has the canonical url moved to wikiba.se?
* Is this a left-over that should be removed?
See also:
* {T166299}