Manual:$wgAllowTitlesInSVG

From MediaWiki.org

SVG: $wgAllowTitlesInSVG
If true, <title> will be allowed in files with an "image/svg" MIME type.
Introduced in version:	1.7.0 (r14084)
Removed in version:	still in use
Allowed Values:	(boolean)
Default Value:	false

Other settings: Alphabetical | By Function

[edit] Details

If true, <title> will be allowed in files with an "image/svg" MIME type.

MediaWiki will reject HTMLesque tags in uploaded files as some browsers can't perform basic stuff like MIME detection and are therefore vulnerable to uploading dangerous/invalid files as images. You should leave this disabled if your web server is mis-configured and doesn't send appropriate MIME types for SVG images.

[edit] Location

Added to localsettings.php but not in localsettings.php by default.