http://w3c.github.io/html-aria/#tr says in the column "Implicit ARIA semantics - SHOULD NOT be used" for element tr:

role=row, may be explicitly declared when child of a table element with role=grid

so for role=table or role=treegrid, <tr role=row> should not be declared explicitly.

The treegrid example in aria-practices uses <tr role=row>.

http://w3c.github.io/aria-practices/examples/treegrid/treegrid-1.html

Should the example omit role=row, or should ARIA in HTML be changed to allow it in role=treegrid?

cc @spectranaut @stevefaulkner @mcking65