Extension default namespaces

To prevent conflicts in new namespaces added by extensions, please list your extension's custom namespaces here on the list of extension default namespaces. If you define a constant for a custom namespace, list it here too.

Note that these are only default namespaces. All extensions defining new namespaces should provide the installer with a method of configuring the extension to use a different range of namespaces for its custom namespaces.

In general, numbers for new namespaces should be reserved in blocks of 10, where no known namespaces are already added by MediaWiki core or any known extensions (see discussion). Namespace numbers between 3000 and 4999 should not be used; these numbers are reserved for wikis to define their own custom namespaces. Furthermore, care should be taken when selecting numbers under 1000, since this range has historically been quite heavily used by extensions and sites alike (numbers under 200 should probably be avoided altogether).

Naturally some namespaces listed on this page will overlap, and violate the recommendations listed here. The recommendations are good practices new extensions should try to adhere to to avoid conflicts; for legacy reasons, old extensions that have already created conflicts and bad practice can't simply be changed but are listed here to help avoid even more conflicts.

Wikimedia Foundation
Many Wikimedia Foundation wikis have site-specific namespaces in this range. Including the Portal namespace (100) on most Wikipedia projects, Creator namespace (100) on Wikimedia Commons, the Extension namespace (102) on mediawiki.org, the Subject namespace (112) on English Wikibooks, and many others.

Wikimedia Foundation

 * Meta-Wiki (meta.wikimedia.org) has custom namespaces in this range:
 * 200: Grants, 201: Grants_talk. – https://meta.wikimedia.org/wiki/Grants:Start
 * 202: Research, 203: Research_talk. – https://meta.wikimedia.org/wiki/Research:Index
 * 206: Iberocoop, 207: Iberocoop_talk. – https://meta.wikimedia.org/wiki/Iberocoop:Portada

Wikia
300 - 399. Wikia has been seen using namespaces in this range for its custom extensions and configurations. To avoid conflicts in case Wikia extensions are ported to work outside of Wikia it would be best to avoid defining new extensions that use this range. Wikia alters the namespaces for some extensions used on its own wikis. Please also take these into account while coming up with new namespace numbers to use in new extensions.

Hidden pages
HiddenPages requires custom namespaces to be added manually. Thus, a specific sequence cannot be registered. Nonetheless, the extension recommends using namespace numbers 1000 and up.

ID 3000+
The range of 3000–4999 is reserved for sites to define their own custom namespaces without fear of conflict. No known extensions define namespaces in this range, and new extensions should avoid it as well.

In accordance with this, the BlueSpice Namespace Manager uses the range above 3000 to create custom namespaces.