When you're upgrading to React 18.3.1 or React 19, this gives you the minimum compatible versions for everything in your dependency tree. It covers the obvious ones like testing-library and react-router, plus the less obvious gotchas like Apollo Client needing 3.8+ for useSyncExternalStore and react-redux v7 breaking in concurrent mode. The decision tree for handling peer dependency conflicts is genuinely helpful, and the guidance on when to actually use legacy-peer-deps (sparingly, with documentation) will save you from future pain. Treat this as your preflight checklist before npm install during a React upgrade.
npx skills add https://github.com/github/awesome-copilot --skill react18-dep-compatibility