If you do

xfd -font \
'-urw-Zapf Dingbats-medium-r-normal--0-0-0-0-p-0-urw-fontspecific'

You get a window with blanks for all the letters.  That appears to me to be
wrong.  I know, however, even when things look really wrong, they can still
be correct, so I hope I'm not just being ignorant here.

By contrast,

xfd -font '-URW-Zapf Chancery-medium-i-normal--0-0-0-0-p-0-iso8859-1'

works correctly.
 
I noticed this problem because Blackdown's JDK 1.2.2 FCS tries to load a
'zapf dingbats' font, which fails.  I'm trying to investigate why that
happens.