In step 4 of the Node / React tutorial for building an embedded app, the AppBridge TitleBar component is introduced. Following the tutorial as written, the Title Bar itself does not show up. It needs a 'title' prop (marked required in the TitleBar docs). With the prop, the title bar works fine.
Here's the component with the bug in the github source for the tutorial:
I spent a couple hours trying to figure out whether my AppBridge was connected correctly, since the TitleBar wasn't showing, and I'm new to the Shopify app dev domain. It turns out, the tutorial code had a bug instead.
Should be a quick fix to the tutorial, and hopefully this helps for anyone else who runs into the bug in the meantime.