In src/declarative/util/qdeclarativepropertymap.h there are lines:

class Q_DECLARATIVE_EXPORT QDeclarativePropertyMap : public QObject
{
    Q_OBJECT
public:
    QDeclarativePropertyMap(QObject *parent = 0);
    virtual ~QDeclarativePropertyMap();

    QVariant value(const QString &key) const;
    void insert(const QString &key, const QVariant &value);
    void clear(const QString &key);

    Q_INVOKABLE QStringList keys() const;
...

but the docs (e.g. http://doc.qt.nokia.com/4.7-snapshot/qdeclarativepropertymap.html) do not list "QStringList keys() const" as one of public functions.

It's really, really nasty that this function is not mentioned in the docs, because this function is incredibly useful: if one just reads only docs then it seems that the only way to loop over all key-value pairs in the map would be to keep track of keys added to the map yourself (which would be a huge overhead)...

UPDATE: it seems to be a problem with all public Q_INVOKABLE functions! For example, src/declarative/qml/qdeclarativecomponent.h has a public function "errorString()" which is not mentioned in the docs (e.g. http://doc.qt.nokia.com/4.7-snapshot/qdeclarativecomponent.html) at all!