Declarative UI for Vaadin Flow
This is basically Vaadin-8-style Declarative UI for Vaadin Flow. The goal is to externalize the layout of the components in your application and have it as much more readable HTML/XML instead of cluttering up your Java code. It's completely interpreted and converted to a Component-tree on the server-side.
Support for additional components and attributes can be added quite easily. The add-on comes with built-in support for Spring Boot to pick up custom
See the Links section for add-ons that try to solve the same problem, albeit in completely different ways.
For Vaadin 14 support, see versions 0.x.