Manual:$wgXhtmlNamespaces

From Linux Web Expert

<translate> Output</translate>: $wgXhtmlNamespaces
Permit other XHTML namespaces in addition to the w3.org default.
<translate> Introduced in version:</translate>1.9.0 (r18943)
<translate> Removed in version:</translate><translate> still in use</translate>
<translate> Allowed values:</translate>(array)
<translate> Default value:</translate>[]

Details

Permit other namespaces in addition to the w3.org default.

Use the prefix for the key and the namespace for the value. For example:

$wgXhtmlNamespaces['svg'] = 'http://www.w3.org/2000/svg';

Normally we wouldn't have to define this in the root ‎<html> element, but IE needs it there in some circumstances.