This feature is still in development.
Eraser check box. When checked, the brush acts as a rubber.
Display the set of configured brushes (MyPaint brushes format). By default, Synfig is installed with a selected set of brushes from “Concept Design (C_D)” pack by Ramon Miranda. From the Preferences Dialog System, you can configure the
Brush Presets Pathto use other brushes package (for example the ones listed by MyPaint)