ListModel(QQmlListModel) inherits QAbstractListModel, which inherits QAbstractItemModel.

There are 'data()' methods in QQmlListModel and QAbstractItemModel to check the model data.

• https://doc.qt.io/qt-5/qabstractitemmodel.html#data

But It is only invokable on QAbstractItemModel. The data() method has to be invokable on the child classes.

qabstractitemmodel.h (QAbstractItemModel)

Q_INVOKABLE virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const = 0;

qqmllistmodel_p.h (QQmlListModel)

QVariant data(const QModelIndex &index, int role) const override;

The history was:

1. QQmlListModel inherits QAbstractListModel:
   - https://git.sailfishos.org/mer-core/qtdeclarative/commit/7daab8039abc32ab5be5706a08cb58905fe0e0b6#37c796b8276181620832233992e5e90b1af4c81d_81_79
2. data() in QAbstractItemModel became Q_INVOKABLE:
   - https://codereview.qt-project.org/c/qt/qtbase/+/107171
3. It seems a mistake not to put an invokable in the child class.