Paolo Abeni [off-list ref] writes:

+      -
+        name: support-nesting
+        type: flag
+        doc: |
+          the device supports nesting shaper belonging to this scope

Nit: capitalize all the doc strings for consistency.

+          below 'detached' scoped shapers. Only 'queue' and 'detached'
+          scope and flag 'support-nesting'.

'and flag' looks like a typo. Do you mean 'can have flag'?

+    -
+      name: cap-get
+      doc: |
+        Get / Dump the shaper capabilities supported by the given device
+      attribute-set: capabilities
+
+      do:
+        request:
+          attributes:
+            - ifindex
+            - scope
+        reply:
+          attributes: &cap-attrs
+            - support-metric-bps
+            - support-metric-pps
+            - support-nesting
+            - support-bw-min
+            - support-bw-max
+            - support-burst
+            - support-priority
+            - support-weight
+
+      dump:
+        request:
+          attributes:
+            - ifindex
+        reply:
+          attributes: *cap-attrs

scope is missing from the dump reply