OmegaWiki used to be based on the "Wikidata" extension of MediaWiki.
However, recently, a new project called the Wikidata project, which is based not on the Wikidata extension, but the Wikibase extension, was started. This confused a lot of people.
At the same time, extensions are being moved from Subversion to Git. Therefore, during that moved I have asked that the Wikidata extension be renamed to WikiLexicalData extension.
Why lexical? The Wikidata extension was initially developed for OmegaWiki, storing words, definitions and translations. It was believed however that the extension could be easily adapted for something else, with little code changes, and that the lexical part of Wikidata would be only one of the possible uses. After several years, there was obviously no interest in using that extension for something else. After having played with the code myself, I now believe that the languages are too central to that extension and that a major rewrite would be needed to code for something else, and probably starting from scratch would be as fast as a major rewrite. This is also why the Wikidata project started from scratch instead of starting from the Wikidata extension.
It is even now considered that in the future, the OmegaWiki database will be kept as is, but the extension code will be rewritten (completely?) to depend on the Wikibase extension (Wikidata project). This, of course, depends on the outcome of the Wikidata project, but it seems to give promising results at the moment :-)
For the user of OmegaWiki, all of this changes nothing.
For the developers, update you Svn to Git, and change the extension name.