This has been deprecated by xorg-server w/ USE=kdrive; not to mention that it's based on xfree-4.3.0 code, so it's probably affected by tons of security bugs.
Most of the security issues I've seen were in the X libraries or the Xorg DDX, so they wouldn't affect kdrive, but I have not done an audit. One problem with removing it is that the new xorg-server-based kdrive cannot be built as small as this standalone package because of (fixable) deficiencies in the new build system. (To test, build xorg-server with USE="kdrive minimal -xorg" -- note, this will leave you with no Xorg server.) I'm going to close this as LATER, pending a kdrive in xorg-server that works as well as the standalone one.
bugzie
Cleaning old bugs with state LATER. This one is fixed. Because kdrive ebuild has been removed.