Acorn is a PHP framework that seamlessly integrates Laravel's core components into WordPress, enabling developers to use Laravel's service container, routing, configuration, caching, and Blade templating within WordPress themes (especially Roots Sage). It provides a custom application bootstrapping process that hooks into WordPress's lifecycle, along with comprehensive asset management (supporting Vite, Bud, and Mix build systems), CLI commands via WP-CLI, exception handling with Whoops integration, and view composers with ACF field support. The codebase is a well-structured library with clean abstractions, extensive test coverage (Pest with snapshot testing), and a devcontainer for integration testing. It is actively maintained with CI workflows to track upstream Laravel foundation updates, though the forked nature introduces moderate technical drift risk.