Instead of specifing an actual device name, the keyword 'removable' can be used
to limit the search of acceptable live media to removable type only. Note that
-cdrom devices are not removable, but e.g. usb mass storage is.
+if you want to further restrict the media to usb mass storage only, you can use
+the 'removable-usb' keyword.
{live-media-encryption|encryption}=**TYPE**::