What is the relationship between Haiku and Qt? Is Qt the
recommended/required graphical toolkit?
Qt has been ported to run in Haiku, but is *not* native. Haiku has its own
which one would normally use if writing a new app -- or even porting one that
doesn't already depend on Qt.
What's the relation to KDE? I see HaikuDepot has a lot of KDE apps (and
has/uses the latest Qt). Is it a good idea to develop KDE apps to run on
KDE is basically Linux, and is related directly to neither Haihu nor Qt.
I didn't know there were any 'KDE' apps on Haiku. Someone else will have
to explain the relation.