Systems

Cross-cutting subsystems inside packages/astro/src/. Each page focuses on one architectural concern and traces the code paths involved.

Page	What it covers
CLI	bin/astro.mjs, src/cli/ command dispatch, the dependency-injection migration.
Dev server	astro dev, vite-plugin-astro-server, restart, port allocation, update checks.
Build pipeline	astro build, BuildPipeline, static generation, SSR adapter handoff.
Routing	Route discovery, manifest, matching, prerendering, redirects, rewrites.
Render context	The per-request RenderContext and how it executes middleware, endpoints, and pages.
Vite plugins	The 20+ internal Vite plugins, in load order.
Error handling	errors-data.ts, the dev overlay, integration errors, user errors.

These pages assume you've read overview / architecture. The features pages under features reference subsystems but focus on user-visible capabilities.