From Macros Wiki
- FILTER_SHAPES <keep/remove> <type>
- Filter the current list of shapes by either keeping just the given type of shape, or removing the given type of shape.
- KEEP or REMOVE
- One of the following shape types
OPEN, CLOSED, DIR_CW, DIR_CCW, SHAPES, HOLES, INNERS or OUTERS
- FILTER_SHAPES REMOVE, OUTERS
- FILTER_SHAPES KEEP, HOLES
This will result in the list of shapes containing only holes that are not outer shapes.