Manual:$wgMimeTypeExclusions

MIME types: $wgMimeTypeExclusions
MIME types to disallow if $wgVerifyMimeType is enabled.
Introduced in version:	1.37.0 (Gerrit change 680806; git #4dae3b1a)
Removed in version:	still in use
Allowed values:	(array of MIME types (strings))
Default value:	(see below)
Other settings: Alphabetical | By function

Details

Files with these MIME types will never be allowed as uploads if $wgVerifyMimeType is enabled.

This variable was previously $wgMimeTypeBlacklist .

Default values

MediaWiki version:

≥ 1.39

$wgMimeTypeExclusions = [
	# HTML may contain cookie-stealing JavaScript and web bugs
	'text/html',
	# Similarly with JavaScript itself
	'application/javascript', 'text/javascript', 'text/x-javascript', 'application/x-shellscript',
	# PHP scripts may execute arbitrary code on the server
	'application/x-php', 'text/x-php',
	# Other types that may be interpreted by some servers
	'text/x-python', 'text/x-perl', 'text/x-bash', 'text/x-sh', 'text/x-csh',
	# Client-side hazards on Internet Explorer
	'text/scriptlet', 'application/x-msdownload',
	# Windows metafile, client-side vulnerability on some systems
	'application/x-msmetafile',
	# Java applets are no longer supported by browsers and may contain cookie-stealing code, similarly to JavaScript
	'application/java'
];

MediaWiki versions:

1.37 – 1.39

$wgMimeTypeExclusions = [
	# HTML may contain cookie-stealing JavaScript and web bugs
	'text/html',
	# Similarly with JavaScript itself
	'application/javascript', 'text/javascript', 'text/x-javascript', 'application/x-shellscript',
	# PHP scripts may execute arbitrary code on the server
	'application/x-php', 'text/x-php',
	# Other types that may be interpreted by some servers
	'text/x-python', 'text/x-perl', 'text/x-bash', 'text/x-sh', 'text/x-csh',
	# Client-side hazards on Internet Explorer
	'text/scriptlet', 'application/x-msdownload',
	# Windows metafile, client-side vulnerability on some systems
	'application/x-msmetafile',
];

Example

If you wanted to allow html files to be uploaded:

$wgFileExtensions[] = 'html';
$wgProhibitedFileExtensions = array_diff( $wgProhibitedFileExtensions, array ('html') );
$wgMimeTypeExclusions = array_diff( $wgMimeTypeExclusions, array ('text/html') );