ECB Templates
From Posstack.com Documentation
Besides the Blank template and premade templates, Easy Content Builder gives you a third option - Create a new template based on existing templates.
This option is only available for the Pro plan. If you already created a custom template before using the Easy Content Builder app, you can reuse and customize this custom template for other pages.
When creating a new template, you will see all existing templates available (if they exist) from the dropdown list like the screenshot below: