在镜像(Mirror)的帮助(Parts and Features\Patterns and Mirroring\Types of Patterns\Mirror Feature\Mirror Feature PropertyManager)中有：

Feature Scope(Available when you mirror features in assemblies or multibody parts.)Specifies which bodies or components you want the feature to affect.

可能是在如上Convert to Mesh Body或Body-Move/Copy1后，有了多实体（进而镜像属性中显示了镜像实体(Bodies to Mirror)）。