When you create a new post as a draft (which is called a branch on git), ExtraStatic automatically creates a preview site for you.
This preview site is a pre-published site that looks identical to your site, on a private url. You can review it without having to modify your existing site. And you can share a private url with a reviewer or collaborator to get feedback.
Preview sites are not permanent; don’t count on them being available for more than a week.
If you edit files on the “draft” (also called a “branch” on extrastatic.dev, a git term), then the preview site will be updated.