Users with full administrative access to the site, including all permissions.

Subscribers can receive notifications, sync the site, comment on content, and appear in the subscribers list.

In the future, subscribers will also be able to read private documents, based on per-document configuration set by Site Owners or Writers.

Users who have permissions to add changes to a Branch created by another user. Also, they can read private documents.

Authors are not a Role; they are the Writers' subset who have edited a document.