Those binaries are part of the package so should be installed as well. Reproducible: Always
mkWDclean is IMHO a tool to fox mkv-headers for broken players. But especially the WDTV (did I read mk"WD"clean?) has already fixed firmware for some months. And many other players are fixed also. But I try to add those binaries also. They're not build in standard compile...
ok, media-video/mkclean-0.8.6-r1 has "mkWDclean" and "mkcleanreg" added. media-video/mkvalidator-0.3.7-r1 has "mkvtree" added. mkvtree is included in both packages in the same version. I decided to add it to mkvalidator, because it fits better there.