The string dndenabled_help,core say:
You can drag one or more files from your desktop and drop them onto the box below to upload them.<br />Note: this may not work with other web browsers
Should be
...<br />Note: this may not work with all web browsers

Context:
Go to a course and add a file using the activity chooser. See the help text behind the blue question mark above the 'Select files' box.