This plugin automatically implements HTTP/2 Server Push for a site's critical JavaScript and CSS files. It is designed for developers and site administrators who want to improve page load performance by reducing the number of sequential network requests. The tool works by sending Link headers for resources that have been enqueued, allowing the server to push assets to the browser before they are explicitly requested.

• Automatic Resource Collection: Collects enqueued scripts and styles registered by themes and plugins, eliminating the need for manual configuration of which files to push.
• Flexible Delivery Method: Uses HTTP headers or HTML link elements based on context. It primarily sends Link headers for optimal HTTP/2 Server Push and gracefully falls back to emitting <link rel="preload"> tags in the HTML if headers have already been sent.
• Customizable Resource List: Allows adding custom assets via a filter. Developers can extend the default list to push additional critical resources like web fonts or hero images using the provided h2push.push_resources filter.
• Host Restriction Controls: Includes a filter to manage allowed hosts. By default, it only pushes resources from the local site, but this can be modified to include assets from specific external domains if needed.
• Backward Compatibility: Provides preload functionality for non-HTTP/2 servers. Even on servers without HTTP/2 support, the plugin can still deliver performance benefits by outputting preload hints for browsers that support them.