You can use that component. It's clientlibs are defined under ui.apps:
"As part of the starter project a dedicated client library for the Responsive Grid has been included in the ui.apps project. You can view the client library at /aem-guides-wknd-events/ui.apps/src/main/content/jcr_root/apps/wknd-events/clientlibs/responsive-grid. This client library has a category of wknd-events.grid and includes a single file named grid.less which includes the necessary CSS for the Layout Mode and the responsive grid to work. Next we will make sure that this CSS is loaded with the React app."
Adobe Experience Manager Help | Getting Started with React and AEM SPA Editor - Chapter 2
Moreover, it's a Layout Container Component:
Responsive Layout
You can use it the same way you can use/create the other components, the way AEM Text component is mapped to a React component.
Adobe Experience Manager Help | Getting Started with React and AEM SPA Editor - Chapter 1