Manual:$wgAjaxLicensePreview

From MediaWiki.org

Uploads: $wgAjaxLicensePreview
Allow preview licences during upload via AJAX.
Introduced in version:	1.11.0
Removed in version:	still in use
Allowed Values:	Boolean
Default Value:	true

Other settings: Alphabetical | By Function

[edit] Details

Users can preview the licenses on Special:Upload before uploading media to the wiki. This setting is on by default and applies only if MediaWiki:Licenses has been created.