kuiviewer 4:19.12.3-0ubuntu1 (s390x binary) in ubuntu focal

 KUIViewer is a utility to display and check user interface (.ui) files
 created in Qt Designer. The interfaces can be shown in a variety of
 different widget styles to ensure that they display correctly in any
 environment.
 .
 The Qt Designer itself is in the package qttools5-dev-tools.
 .
 This package is part of the KDE Software Development Kit module.