qtbase/src/corelib/tools/qmap.h contains the following to-do comments (duplicated in both itersator and const_iterator):

        // ### Qt 5: get rid of 'operator Node *'
        inline operator QMapData::Node *() const { return i; }
...
    private:
        // ### Qt 5: remove
        inline operator bool() const { return false; }

These were added by commit 1913214773bb31bb2f3b6f42f293a9d91062b52c in the private history, which made the same notes in qhash.h, though those have already been removed.

These comments should either be actioned for 5.0.0, removed, or changed to Qt 6 to-do's.