Manual:$wgMimeType

Output: $wgMimeType
The type to send in the Content-Type header.
Introduced in version:	1.3.0
Removed in version:	still in use
Allowed values:	(string)
Default value:	'text/html'

Other settings: Alphabetical | By Function

Details

The type to send in the Content-Type header of pages. Set to "application/xhtml+xml" if you want pages to be treated as XHTML. Also "application/xhtml+xml" is necessary to display MathML properly in Mozilla.