Given that the ebuild does call java build functions, I infer that this is a bug and not intended (otherwise I would suggest a rename to domination-bin).
>>> Compiling source in /tmp/portage/games-board/domination-22.214.171.124-r2/work/Domination ...
java-pkg-2_src_compile: build.xml not found so nothing to do.
>>> Source compiled.
Created attachment 833573 [details]
the -bin is just to distinguish the source code package from the binary package IFF there are both. I fully agree, this is not ideal and misleading.
There had been discussions about how to improve the situation see:
I close it because it is not a bug, but a (bad?) specification.
^ agreed that it shouldn't be renamed, although that the ebuild is trying to compile it when it's prebuilt is silly
so I'll keep the bug open as a reminder whenever someone looks at this package