Binary package “libphonon4qt5experimental-dev” in ubuntu focal

multimedia framework from KDE using Qt 5 - experimental development files

 Phonon is a Qt 5 multimedia API, which provides a task-oriented abstraction
 layer for capturing, mixing, processing, and playing audio and video content.
 .
 This package contains the development files needed to build Phonon back-ends
 or internal applications which need the Phonon-Experimental library.
 Third-party applications should not depend on this library. Please read
 README.Debian if you are considering a build-dependency on this package.