The group role - ARIA Reference Guide

Composites
Represent containers for navigating interactive descendants.
Landmarks
Represent top-level sections of a page, relevant to a specific purpose, that a user may want to scan for quickly and could appear in a site map or table of contents.
Live Regions
Represent dynamic content or announcements, typically updated as a result of an external event when user focus may be elsewhere.
Structures
Represent non-interactive parts of a page that organize content into coherent units.
Widgets
Represent focusable, interactive elements.
Windows
Represent inner windows that are children of the main web document.

WAI-ARIA spec HTML-ARIA spec

Structure(opens in new window)Flow Content(opens in new window)

Description

A set of user interface objects that is not intended to be included in a page summary or table of contents by assistive technologies.

Allowed Content

Flow content

HTML Elements with Implicit ARIA Role

details
fieldset
optgroup

Allowed HTML Elements

details (role attribute unnecessary)
dl
fieldset (role attribute unnecessary)
figcaption
footer
header
menu
ol
optgroup (role attribute unnecessary)
ul
div, span, p, other elements that can receive any role