A WMTS CoverageReader would allow GeoServer to publish cascading WMTS layers.
A draft working implementation foresee:
extension/xsd/xsd-wmts: emf modeling
unsupported/wmts: Logic for handling the WMTS GetCapabilities; WMTS client
extension/xsd/xsd-core: Upgrade version of org.eclipse.emf
unsupported/tile-client: minor compat changes
!!! Since the related changes in GeoServer cannot be enclosed in a single community module but need changes in the ``main`` and other core modules, the needed GeoTools classes should be promoted out from the ``unsupported`` status.