In February 2025, a categorization feature for the data namespace was [[ https://www.mediawiki.org/wiki/Extension:Chart/Project/Updates | added ]] to Wikimedia Commons (T242596). These categories are defined in the JSON data of the page using the `mediawikiCategories` parameter. Pages in this namespace do not support wikitext and will throw a `content format text/x-wiki is not supported by the content model Tabular.JsonConfig` error if wikitext is added.
Currently, this means that category tools like HotCat or Cat-a-lot will not work for these pages and support for JSON content model should be added to these tools.
Example pages which are using mediawikiCategories parameter:
* https://commons.wikimedia.org/wiki/Data:Acqua_alta_Venezia_Interventi_annuali_MOSE.tab
* https://commons.wikimedia.org/wiki/Data:Okome.map
* https://commons.wikimedia.org/wiki/Data:Sweden_-_yearly_population_and_population_changes.chart
Parameter is used in [[ https://www.mediawiki.org/wiki/Help:Map_Data | maps ]], [[ https://www.mediawiki.org/wiki/Extension:Chart | charts ]] and [[ https://www.mediawiki.org/wiki/Help:Tabular_data | tabular data ]] in Wikimedia Commons. From Cat-a-lot perspective all of these are json formatted data with mediawikiCategories value.