Bind mounts should be in the list of special devices

I have some entries in my /etc/fstab which are bind mounts:

/mnt/hdd/sources /src none defaults,bind 0 0

duf shows them in the list of normal, non-special devices, but I think they should be either hidden or shown in the special devices section. There doesn't seem to be a good way to detect a bind mount other than parsing /etc/fstab.