This repo contains a collection of packages for using Shopify’s Argo for Checkout. You’re probably looking for @shopify/argo-checkout, which has all of the typings for the API available to Argo extensions. It also has documentation for the available global API, extension points, and components.
This repo also has some of the helper packages Shopify uses to make Argo extensions easy to develop and deploy:
@shopify/argo-runis a tiny asset dev server and production asset builder, powered by webpack@shopify/argo-webpack-hot-clientis an Argo-compatible replacement for webpack-hot-client that enables auto-reloading in Argo extensions.