Quick and dirty WP endpoint to redirect to a download of attached file for a latest GitHub release.

## github-release-download.php
<?php
declare( strict_types=1 );

new class( 'Rarst', [ 'laps' ] ) {

	private $owner, $repos;

	private $endpoint = 'download';

	public function __construct( string $owner, array $repos ) {
		$this->owner = $owner;
		$this->repos = $repos;

		add_action( 'init', [ $this, 'init' ] );
	}

	public function init() {

		add_rewrite_endpoint( $this->endpoint, EP_ROOT );

		add_filter( 'posts_where', [ $this, 'posts_where' ], 10, 2 );
		add_filter( 'template_include', [ $this, 'template_include' ], 9 );
	}

	public function posts_where( $where, $query ) {

		if ( isset( $query->query[ $this->endpoint ] ) ) {
			return ' AND 1=0';
		}

		return $where;
	}

	public function template_include( $template ) {

		global $wp_query;

		$repo_name = $wp_query->query[ $this->endpoint ] ?? '';

		if ( ! in_array( $repo_name, $this->repos, true ) ) {
			return $template;
		}

		$transient_key = "latest-release-{$this->owner}/{$repo_name}";
		$api_url       = "https://api.github.com/repos/{$this->owner}/{$repo_name}/releases/latest";
		$release_url   = "https://github.com/{$this->owner}/{$repo_name}/releases/latest";
		$response      = get_transient( $transient_key );

		if ( empty( $response ) ) {
			$response = wp_remote_get( $api_url );
			$response = wp_remote_retrieve_body( $response );

			if ( empty( $response ) ) {
				wp_redirect( $release_url );
				die;
			}

			set_transient( $transient_key, $response, 15 * MINUTE_IN_SECONDS );
		}
		$response     = json_decode( $response );
		$redirect_url = $response->assets[0]->browser_download_url ?? $release_url;

		wp_redirect( $redirect_url );
		die;
	}
};