Wikidata and Data Items are separate projects powered by the same software, similarly to how OSM Wiki and Wikipedia both use Mediawiki.
- wikidata=* links to Wikidata items
- "Data item" links on the sidebar of some pages on this wiki link to Data Items
Consequently, the Q243 identifier may refer to the Data Item Key:dog or the Wikidata Item Eiffel Tower. It was suggested to change the first letter for each Wikibase installation to differentiate between them. However, this suggestion was declined by the Wikidata product manager, because each letter represents the type of entry. Apart from letter
Q, there are also the letters
M representing properties, lexemes, forms, senses, entity schemas, and MediaInfo respectively.