Backstage logbook: Migrating the Catalog Plugin to the New Frontend System

Before we start: where are we? This post assumes you've already done the initial hybrid-mode migration — switching createApp to the new version, wrapping legacy options and your root component with the compatibility helpers, and confirming the app still boots. If you haven't done that yet, follow the official migration guide first and come back. That part is fairly mechanical and the docs cover it well. Once your app is running in hybrid mode, you have something like this: a FlatRoutes tree that still manually wires up all your routes (including the catalog ones), and a large EntityPage.tsx that manually composes tabs and cards for every entity kind. At this point, convertLegacyAppRoot is doing the heavy lifting of keeping things working while we incrementally replace them. Step 1: Drop in the new Catalog plugin The first real NFS(new frontend system) step is to import the catalog plugin from its alpha entrypoint and add it to your createApp features list: import catalogPlugin from ' @