Hello, and welcome!
There's nothing really to report. As the release announcement noted, the architectures all have different numbers of packages available:
Code:
alpha: 7450
amd64: 9295
hppa: 6304
i386: 9290
mips64: 7094
mips64el: 7846
powerpc: 8383
sh: 111
sparc: 1105
sparc64: 8528
Not only are some applications architecture-specific, in order to have an application package available for an architecture, all of its build and run dependencies must also be available. Lumina requires 413 dependencies (build, run, or both), and all must be available on macppc in order for Lumina to be used there.
While I was running
$ make full-all-depends | wc
in order to get that number for you, I also looked at the port Makefile, and noted that Lumina requires Qt5. Qt5 on OpenBSD requires gcc 4, and while gcc 4 is available on nine architectures ... macppc is not one of them.
Edited to add:
"powerpc" is in the architecture list for gcc 4. I was looking for "macppc." But Qt5 is not available for macppc, so there must be a Qt5 dependency which is not available on the platform.