MarsSeed [1] filed a deletion request for kdesudo [2]:

It's been deprecated for years now, please delete it. Users can use kdesu, it can be configured to use sudo instead of su.

https://www.reddit.com/r/kde/comments/8au9r8/alternative_to_kdesudo/

Launchpad source last updated in 2011. It informs the user as such: Moved to KDE https://projects.kde.org/kdesudo

But the latter is not found. If it's ever existed, it has been discontinued completely.

[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/kdesudo/