Nokia spaguetti development strikes again
I believe that functionality was initially thrown as a bone to the Maemo/N900 community but when they weren't seduced with MeeGo AT ALL it became vapourware and was never delivered. At least it seems to have been evicted from Maemo6 (Harmattan/N9/N950), which is purely Qt.
From talk.maemo.org:
"Harmattan is really renamed Maemo6 with the Hildon UI replaced by Qt. It should keep backward compatibility, unless your application relies on a Maemo component replaced in Harmattan by Qt component. Which one are these? Only Nokia devs know.
MeeGo (as meego.com) on the other hand uses GTK+ for the Netbook UI and Qt for Handset UI. There are no plans on supporting Hildon on Netbook or GTK+ at all on Handset.
But you may roll your own GTK+ installation for Handset UI, as there in none in standard, so you will not conflict anything."
I don't believe the N900 community will bother to do a Hildon library for Harmattan now, because most of them sneer at the N9 and feel just fine in the GTK+ castle with their beloved N900 (until it breaks, that is). Most of them seem to be desktop developers that like to take a desktop in their pocket, not mobile developers. From that POV, the N9 (and the Swipe UI) do not work.
Don't know what this Hildon has to do with AndyO's Hildon: http://www.theregister.co.uk/2011/11/21/nokia_hildon_the_great_lost_platform/
And for the rest of the UI sad story of foodfights, why Maemo and Moblin were both GTK+ but because of Symbian (and Nokia GTK+ library developers' idiocy) Nokia had to use Qt, another AndyO saga: http://www.theregister.co.uk/2011/03/10/nokia_ui_saga/
Thankfully QtQuick/QML seems to be very, very good. Unfortunately, it's been killed with extreme prejudice. Only the lucky ones with an N9/N950 will ever see it.