We can get the metadata form the C++ plugin and set that for the kpackage.
This way the files are not duplicated in source, on disk and in memory.
Task: https://phabricator.kde.org/T14983
Taken from commit 4ce9a4a915511acbd41450da486d8e5d5bae10da in plasma-desktop
The commit history of the KCM can be followed in 9db1c0593e84cdb705fc61cddbdc4e5a9c318b97
Volker Krause
Nicolas Fella
Alexander Lohnau
Henri Chain