The component AdvancedTimer.qml in note_names adds extra features to standard QML Timer (pause, resume etc.): https://cgit.kde.org/gcompris.git/tree/src/activities/note_names/AdvancedTimer.qml
It is to be made a core element which can be used by other activities in the future, and potentially by some activities presently to refactor the Timer code in them (need to check them out).