We usually list the licenses from the third party components. You can find the list here: http://qt-project.org/doc/qt-5.0/qtdoc/licenses.html
Therefor we follow Digia's recommendation:
"Digia gratefully acknowledges these and other contributions to Qt. We recommend that programs that use Qt also acknowledge these contributions, and quote these license statements in an appendix to the documentation."
All the KDE contributions in the Qt core libraries fall under LGPL, even if they might have a different license elsewhere. This only applies to core Qt contributions, not external libraries from the KDE project of course.