Specifying a default file for error messages (404).

[HTTP-Settings]
DefaultFile=showerr.html          ; Default: -

The DefaultFile allows to specify a file whose content is returned instead of a 404 file not found message. This is a new feature in V2.3.3. In case the URL refers to a not existing file, then this file is fetched. If DefaultFile is not specified then the regular 404 file not found return occurs.