Manual:$wgUploadStashMaxAge

Files and file uploads: $wgUploadStashMaxAge
The maximum age of temporary (incomplete) uploaded files.
Introduced in version:1.20.0
Removed in version:still in use
Allowed values:(integer)
Default value:6 * 3600 (6 hours)

Details edit

The maximum age of temporary (incomplete) uploaded files. Used only by the cleanupUploadStash.php maintenance script.