At this point, the tuning element has been worked out for string instruments only. However, as it seems applicable for other instruments, it's been made available in the MEI.shared module.
<elementSpec ident="tuning" module="MEI.shared">
<desc xml:lang="en">Describes the tuning of an instrument.</desc>
<classes>
<memberOf key="att.common"/>
<memberOf key="att.tuning.log"/>
<memberOf key="att.tuning.vis"/>
<memberOf key="att.tuning.ges"/>
<memberOf key="att.tuning.anl"/>
<memberOf key="model.staffDefPart"/>
</classes>
<remarks xml:lang="en">
<p>At this point, the tuning element has been worked out for string instruments only.
However, as it seems applicable for other instruments, it's been made available in
the MEI.shared module.</p>
</remarks>
</elementSpec>