BuddyPress.org

Can anyone tell me what BuddyPress feature and/or plugin is being used on the BuddyPress Codex to generate the sidebar “Contents” section from headings? Is the process automatic (e.g., as with Mediawiki) or must the Contents section be created manually?

See, e.g., http://codex.buddypress.org/theme-development/wordpress-to-buddypress-theme/ (sidebar “Contents”).