This is contingent on IA2 1.2.1 point release introducing a new role that is distinct from IA2_ROLE_NOTE. We still need to figure out how to normalize how we expose aria role=complementary and how we expose html:aside.
David, gfb or mentored thing?
Note we currently map html:aside internally to ROLE_NOTE (and IA2_ROLE_NOTE).
I'm not clear on what should be done here. It looks like we follow the spec   file:///Users/alex/mozilla/html-api-map/index.html