By lightcubeThis free scripted modifier plugin is designed to clean up some things in a mesh to make it export more cleanly.
This can be helpful in situations where you have either applied multi-channel mapping to an object or used Vertex Paint on it, and later detached elements into other nodes--leaving unused mapping vertices in the node. With this modifier, you can remove those vertices without collapsing the stack, which might be beneficial depending on what you are doing.
Generally this modifier is suited for models that use smoothing groups. Explicitly set normal are not preserved in the modifier.