Well, the topic is called “playground”, so doesn’t hurt to check things out, just need some GTK4 apps to check out, so far most I tried our bound to/or require rust. (and for those I need to switch to nightly)
EDIT: First let’s create a recipe for it here. 
Haruna 1.8.1 is released, not to the Haiku public (so far we got enough media players 
). For this a patch has been upstreamed to fix building for system not supporting DBus. Since this is one I’ve been following for a long time, I keep up with upstream releases.
Playing around with Qt6, 6.11.0 had some weird font issues here, so with the new release for 6.11.1 I thought I’d give it a spin again. Looks like that font issue is resolved. 
With Qt6 and KDE mostly on par I did some digging into GTK4, for this updated glib2 to 2.88.1, GTK4 to 4.22.4, libadwaita to 1.9.0, added a few local packages required for building GNOME packages in Terminal.
Since some of the sources I’ve tried require rust, I do most of these tests in nightly (TLS fix not in beta5).
So far in the last days spend time on Fractal (still has an issue with one of the rust crates where we don’t support memfd), Ghex and Gitte up and running.
For Gitte I always ended up with: undefined reference to iconv_open while linking, using RUSTFLAGS eventually did the trick there.
export RUSTFLAGS+=“-L/boot/system/develop/lib -liconv”
