They're strictly DVD-only, so it's better to mark them as such. This
also documentes the "title" (now renamed to "dvd-title") property.
This also avoids collision with the --title option. (Technically, there
was no problem. But it might be confusing for users, since we have a
policy of naming properties and options the same if they refer to the
same underlying functionality.)
wm4
8a75b19cd4