Edit user interface: $wgUseAutomaticEditSummaries
Whether MediaWiki should make automatic edit summaries.
Introduced in version:1.13.0 (r34562)
Removed in version:still in use
Allowed values:(boolean)
Default value:true

Details edit

If user doesn't specify any edit summary when making an edit, MediaWiki will try to automatically create one. This feature can be disabled by setting this variable to false.