It builds examples and then throws them away, for example plaintextedit. They probably should be disabled in CMakeLists.txt to make the build lighter.
Fixed. mfg Tobias
A commit references this bug: Author: tcberner Date: Sun Jun 23 13:39:36 UTC 2019 New revision: 504953 URL: https://svnweb.freebsd.org/changeset/ports/504953 Log: textproc/kf5-sonnet: disable building of examples - examples are built but not installed, so don't build them PR: 238710 Reported by: yuri Changes: head/textproc/kf5-sonnet/Makefile head/textproc/kf5-sonnet/files/patch-CMakeLists.txt