plymouth-theme-ubuntu-text binary package in Ubuntu Focal s390x

 Plymouth provides a boot-time I/O multiplexing framework - the most obvious
 use for which is to provide an attractive graphical animation in place of
 the text messages that normally get shown during boot. (The messages are
 instead redirected to a logfile for later viewing.) However, in event-driven
 boot systems Plymouth can also usefully handle user interaction such as
 password prompts for encrypted file systems.
 .
 This package contains the default ubuntu-text text theme used when no
 support for a graphical theme is found on your system.

Source package