Documentation unclear on operator== for QModelIndex

Documentation on QModelIndex::operator==() and QPersistentModelIndex::operator==()
The documentation reads: "All values in the model index are used when comparing with another model index."

The meaning of "all values" is not clear and nowhere defined. 
From the implementation of the above functions it is clear that the following are compared:
row, column, internal data pointer and model.

The assumption is made that it is the above, but perhaps this can be stated more clearly.