Manual:$wgAjaxUploadDestCheck

Ajax: $wgAjaxUploadDestCheck
Enable Ajax check for file overwrite, pre-upload.
Introduced in version:1.11.0
Removed in version:still in use
Allowed values:(boolean)
Default value:true

DetailsEdit

Enable Ajax check for file overwrite, pre-upload.

This is not related to the deprecated action=ajax ($wgAjaxExportList) functionality.