Data are a collection of values that convey information, describing the quantity, quality, facts, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted formally.

In Commons data can only be stored in the "Data:" namespace. They can be used for two types of datasets:

• Tabular Data with suffix .tab, allowing users to create CSV-like tables of data. More information: Help:Tabular Data in Mediawiki.
• Map Data with suffix .map, allowing users to store GeoJSON data. More information: Help:Map Data in MediaWiki.
• Chart definitions, with suffix .chart, allowing user to create interactive diagrams.

More information: Commons:File types, Data files.

General remarks:

• Pages in the Data namespace should be in JSON. More information in MediaWiki: mw:Extension:JsonConfig.
• It is required that a table in Data space be in JSON. Data space should not contain tables with regular wiki code.
• It is technically not possible to change a Data namespace to a gallery page (or any other namespace); any corresponding gallery page should be created as such.
• Data defined in Commons can be reused globally on other Wikimedia projects (example) via Lua's mw.ext.data.get. As of January 2025, there is no list of usage in other projects, neither in a "file usage" section on the Data page nor via Special:WhatLinksHere; see phab:T371300.