About
Expo Desktop [github] [youtube] [speakerdeck] adds best-effort macOS and Windows support to Expo apps. It is an independent project by Jamie Birch, not endorsed or maintained by Expo.
It consists of the expo-desktop CLI, plus several supporting libraries (like expo-desktop-config-plugins), that together allow you to create an app and run it for iOS, Android, Web, macOS, and Windows.

Quickstart
After following the prerequisites, create an app like so:
# Create the app.
npx expo-desktop@latest create-app
cd MyApp
# Generate the Xcode, Gradle, and MSBuild projects.
node --run prebuild… then run your chosen target!
node --run ios
node --run android
node --run web
node --run macos
node --run windows