This is an enhancement request. The KDE3 digital clock allowed the selection of multiple time zones. When the mouse was hovered over the clock, a popup panel would appear showing the time in each of the time zones. This is a really nice feature for those that have contacts in various regions of the world.
This isn't something we can (or should) implement in fedora locally. Feature requests should go upstream to bugs.kde.org please. When/if you do, please let us know, so we can track the upstream feature request, and possibly help if able.
Wishlist bug added, https://bugs.kde.org/show_bug.cgi?id=174890
thanks again!