If tstamp2 is not provided, then the extender should be drawn based on the value of tstamp2 on the harm ancestor.
<classSpec ident="att.f.vis" module="MEI.visual" type="atts">
<desc xml:lang="en">Visual domain attributes.</desc>
<classes>
<memberOf key="att.altSym"/>
<memberOf key="att.color"/>
<memberOf key="att.extender"/>
<memberOf key="att.placementRelStaff"/>
<memberOf key="att.visualOffset"/>
<memberOf key="att.xy"/>
</classes>
<remarks xml:lang="en">
<p>If <att>tstamp2</att> is not provided, then the extender should be drawn based on the value
of <att>tstamp2</att> on the harm ancestor.</p>
</remarks>
</classSpec>