Each topic can have one or more files of any type attached to it by using the Attach screen to upload (or download) files from your local PC. Attachments are stored under revision control: uploads are automatically backed up; all previous versions of a modified file can be retrieved. ... Attachment names are stored directly in the server native file system, so filenames are sanitized to prevent use of names that would be unacceptable to the variety of platforms where Foswiki is supported. ...