startkde uses "which", but the dependency on it is missing in the kdebase package.
It's there in a round-about way, kdebase includes currently: Requires: sh-utils I'll see if we can clean that up, ie, s/sh-utils/coreutils/
coreutils does not require "which" either, and "which" doesn't provide sh-utils. arts >= 8:1.5.7-7 on the other hand does have a dependency on "which", so if you wish to rely on other packages pulling "which" in (which is something I wouldn't personally do as it's directly required by kdebase and could change in arts), that one should work.
duh, you're right, of course.
found xargs usage too. %changelog * Wed Oct 03 2007 Rex Dieter <rdieter[AT]fedoraproject.org> - 6:3.5.7-17 - Requires: findutils which (#312611)