The idea of this document is to imagine an implementation of a browser plugin for elm-ui, similar to Vue devtools or React Developer Tools.
These developer tools add new panels to the browser's devtools whenever Vue or React components are detected.
It is not fully specified what exactly an elm-ui "devtool panel" could be able to do. The bare minimum requirement is to visualize the "element tree" similar to the way the Inspector panel lets you visualize the DOM tree.