KDE su executes kdesu_stub through su or ssh. The stub is running as the target user. After some information is sent via stdin and stdout the stub executes the target program. The information passed over are the X display, a X authentication cookie (if available), the PATH and the command to run.
KDE su uses a stub program because the X cookie is private information and therefore cannot be passed on the command line.
Releases
4 releases since Debian 3.1 (Sarge); the text changed 1 time.