When WPE is built with Qt support, the QML plugin in installed in ${libdir}/qml/org/wpewebkit/qtwpe/ , however that's not part of the default import path, so I have to set QML2_IMPORT_PATH manually in order to run the minibrowser.
Created attachment 390763 [details] Patch
Comment on attachment 390763 [details] Patch More changes are needed, in Tools/glib/api_test_runner.py and Tools/Scripts/run-qt-wpe-minibrowser
Created attachment 390906 [details] Patch
Committed r256727: <https://trac.webkit.org/changeset/256727>