Where do I find a Qt plugin for Wayland?

Each time BackInTime runs to perform a backup, I get the messages below about Qt plugins for Wayland. The one about “found a plugin, but yuk ptui!” is confusing. It may be a result of BIT becoming abandonware; the error does not occur on a Tumbleweed system, although that system has an active desktop.

This is on a server that does not have a desktop running.

2020-11-01T07:00:03-0700 sma-server3 kwalletd5[25897]: Failed to create wl_display (No such file or directory)
2020-11-01T07:00:03-0700 sma-server3 kwalletd5[25897]: qt.qpa.plugin: Could not load the Qt platform plugin "wayland" in "" even though it was found.
2020-11-01T07:00:03-0700 sma-server3 kwalletd5[25897]: 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.
2020-11-01T07:00:03-0700 sma-server3 dbus-daemon[15108]: [session uid=1000 pid=15108] Activated service 'org.kde.kwalletd5' failed: Process org.kde.kwalletd5 received signal 6

Not a backintime user, but I note the man page mentions about configuration in a headless environment…