Blueprints
A blueprint (definition) is like a container. Blueprints have controls that allow Frontender Desktop to render the configuration UI used to edit the container instructions (config). Blueprints are used as a template to create containers. They are preformatted to container useful default settings that can be overridden once they have been included onto a page.
Blueprints are created by clicking the icon in the right click menu of a page.
You can update blueprints by clicking the update blueprint checkbox in the container settings menu.

Blueprints are (JSON) definitions. These definitions contain instructions for the templates.
When blueprints are imported (uploaded into Frontender Platform) any referenced blueprints and/or assets (templates, css, js, media) may also be included in the extension package.
More information about blueprints can be found here.