If you are using Linux/Mac, you may use the "grep" command.
e.g
$ grep -rn "class.*NumberAnimation" *
quick/util/qquickanimation_p.h:321:class Q_QUICK_PRIVATE_EXPORT QQuickNumberAnimation : public QQuickPropertyAnimation
quick/util/qquicksmoothedanimation_p.h:46:class Q_AUTOTEST_EXPORT QQuickSmoothedAnimation : public QQuickNumberAnimation
quick/util/qquickspringanimation_p.h:45:class Q_AUTOTEST_EXPORT QQuickSpringAnimation : public QQuickNumberAnimation