qmlcompiler is open source and the new qmlsc is also open source. It's just the extensions that helps making your qml code compatible with the new compiler that isn't open source. This is indeed annoying but not everything is commercial only.
Where can I find the source code for qmlcompiler and qmlsc?
qmltc and qmlcachegen are available in the qtdeclarative.git repo (on either code.qt.io or GitHub) but i can't find qmlcompiler nor qmlsc anywhere. I believe they are commercial only under the "Qt for Device Creation" license.
