“Web Component DevTools” is a Chrome Extension for Chrome DevTools that adds support for Web Components / Custom Elements.
Web Component DevTools is aimed at all developers working with Web Components. The tooling provided creates a new Chrome Devtools panel, which allows a quick look at the custom elements on the current page, and enables modification of attributes and properties of said components.
Shown above is a screenshot of GitHub — who are known for using Web Components a lot — with the “Web Component DevTools” extension open.