kdiff3-qt binary package in Ubuntu Xenial s390x

 KDiff3 compares two or three input files and shows the differences
 line by line and character by character. It provides an automatic
 merge facility and an integrated editor for comfortable solving of
 merge conflicts. KDiff3 allows recursive directory comparison and
 merging as well.
 .
 This version of KDiff3 is stripped-down so that it doesn't depend
 on the KDE libraries. The package "kdiff3" contains the full-featured
 version of the program.

Source package