KMplayer is not (just) a frontend to Mplayer. If nothing else it can use the Xine backend just as well. Not to mention, it's a KPart plugin in the first place. I think the description should change into something like "Video player plugin for Konqueror and basic MPlayer/Xine/ffmpeg/ffserver/VDR frontend for KDE" as quoted from the project's homepage.
Indeed, the description doesn't reflect todays KMPlayer features. Thanks for the report.