You can add and modify the layers.
Examples
<SMS_LAYERS>
<SMS_LAYER NAME="Default" PURPOSE="Default layer for all data"/>
<SMS_LAYER NAME="OutContour" PURPOSE="Layer for the contour geometry"/>
<SMS_LAYER NAME="Openings" PURPOSE="Layer for the inner contour geometry"/>
<SMS_LAYER NAME="Marking" PURPOSE="Layer for the marking geometry"/>
<SMS_LAYER NAME="AntiMarking" PURPOSE="Layer for the anti-marking geometry"/>
<SMS_LAYER NAME="PartInfo" PURPOSE="Layer for the part text information"/>
<SMS_LAYER NAME="Annotation" PURPOSE="Layer for the Annotation"/>
</SMS_LAYERS>
Layer name used in the SMS_STYLE:
<SMS_STYLE>
<LAYER>OutContour</LAYER>
<COLOR>Gray</COLOR>
<LINEWEIGHT>Normal</LINEWEIGHT>
<LINETYPE>Normal</LINETYPE>
</SMS_STYLE>
You can turn on and off the layer in AutoCAD or another CAD tool:
