Our primary goal for developing Public API was to give an opportunity for developers to build custom components, which can manipulate Editor's state, use external APIs and even be shown in posts, generated by Editor, so companies can use them for optimizing the time of creating beautiful posts. For example, you can integrate your product base or dynamic widgets into the post editor.
API for custom component creation in the post editor is available only on the Enterprise plan.
Please find the link to the detailed technical documentation.