This is a 2D/3D tool to select a feature or surface and reuse it as a copy or to apply to another area of the model or drawing.

For example to copy a transitional surface, or unique feature and apply it to other primitive elements.

The idea is to be able to replicate complex features in an easier way from the active model or from an attachment instead of redrawing or copying the entire solid/surface and exploding it to redraw the feature.