http://drupalcode.org/viewvc/drupal/contributions/modules/feeds/includes/FeedsImporter.inc?r1=1.20&r2=1.21

directly in the textfield rather than uploading them through the UI, you will
have to adjust your importer's File Fetcher settings.

Fall back to the target key if a target option is not available. This avoids an ugly notice and allows for processors offering dynamic targets that can be added on the fly.

#840350 lyricnz: (Optionally) Transliterate enclosure filenames to provide protection from awkward names.