after ->15.2, cmd-line Qt apps launch FAILS:"no Qt platform plugin could be initialized" ?

[pgnd]

I upgraded a working Leap 15.1 -> 15.2

 lsb_release -rd
  Description:    openSUSE Leap 15.2
  Release:        15.2

I run KDE from,

 zypper lr -u | grep KDE
  10 | KDE-Applications   | KDE-Applications            | Yes     | (r ) Yes  | Yes     | http://mirror.karneval.cz/pub/linux/opensuse/repositories/KDE:/Applications/KDE_Frameworks5_openSUSE_Leap_15.2
  11 | KDE-Extra          | KDE-Extra                   | Yes     | (r ) Yes  | Yes     | http://mirror.karneval.cz/pub/linux/opensuse/repositories/KDE:/Extra/KDE_Applications_openSUSE_Leap_15.2
  12 | KDE-Frameworks5    | KDE-Frameworks5             | Yes     | (r ) Yes  | Yes     | http://mirror.karneval.cz/pub/linux/opensuse/repositories/KDE:/Frameworks5/openSUSE_Leap_15.2
  13 | KDE-Qt5            | KDE-Qt5                     | Yes     | (r ) Yes  | Yes     | http://mirror.karneval.cz/pub/linux/opensuse/repositories/KDE:/Qt5/openSUSE_Leap_15.2

yast2 & kate are both installed

 rpm -qa yast2 kate
  kate-20.04.3-lp152.1.1.x86_64
  yast2-4.2.83-lp152.1.1.x86_64

both exec/function with no error if launched from kickoff menu or desktop icon click.

attempts to launch either from shell FAIL,

 
kate test.txt
  No protocol specified
  No protocol specified
  This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

  Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

  Aborted

 yast2
  No protocol specified
  No protocol specified
  This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
  
  Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.
  
  /usr/sbin/yast2: line 468: 27000 Aborted                 $y2ccbin $Y2UI_ARGS "$@"

What specific 'Qt plugin' needs to be (re)installed to get cmd line execs operational?

[pgnd]

rm'ing & re-creating ~/.Xauthority solves the problem.

no idea _why_ it didn't 'survive' the upgrade, and, afaict, no explicit indication that .Xauthority is, or is involved in, the problem ...

in any case, sorted.