Manual:$wgUploadSizeWarning

Files and file uploads: $wgUploadSizeWarning
Warn if uploaded files are larger than this.
Introduced in version:1.3.0
Removed in version:still in use
Allowed values:(integer >= 0)
Default value:false (1.13+)

150 * 1024 (1.5-1.12)

150000 (1.3-1.4)

Details edit

Warns the user if they attempt to upload a file larger than this value, specified in bytes. Setting $wgUploadSizeWarning to zero bytes will disable the warning. If triggered, the warning will inform the user that files are recommended to be smaller than this value. The user can choose to ignore the warning and upload the file.

See also edit