Holly just signed up for a new Confluence Cloud site.

When Holly signed up for a new Confluence Cloud site, two groups were definitely created along with the site. These are the default groups for Confluence: confluence-users and site-admins. The confluence-users group grants access to Confluence and allows users to create and edit pages. The site-admins group grants administrative privileges for Confluence and allows users to manage global settings, templates, permissions, and more12

References = Manage product access, Manage groups