woocommerce/plugins/woocommerce-admin/bin/generate-feature-config.php

<?php
/**
 * Generates an array of feature flags, based on the config used by the client application.
 *
 * @package WooCommerce Admin
 */

/**
 * Get phase for feature flags
 * - development: All features should be enabled in development.
 * - plugin: For the standalone feature plugin, for GitHub and WordPress.org.
 * - core: Stable features for WooCommerce core merge.
 */

$phase = getenv( 'WC_ADMIN_PHASE' );

if ( ! in_array( $phase, array( 'development', 'plugin', 'core' ), true ) ) {
	$phase = 'plugin'; // Default to plugin when running `npm run build`.
}
$config_json = file_get_contents( 'config/' . $phase . '.json' );
$config      = json_decode( $config_json );

if ( ! empty( getenv( 'WC_ADMIN_ADDITIONAL_FEATURES' ) ) ) {
	$additional_features = json_decode( getenv( 'WC_ADMIN_ADDITIONAL_FEATURES' ), true );
	if ( is_array( $additional_features ) ) {
		foreach ( $additional_features as $feature => $enabled ) {
			$config->features->$feature = $enabled;
		}
	}
}

$write  = "<?php\n";
$write .= "// WARNING: Do not directly edit this file.\n";
$write .= "// This file is auto-generated as part of the build process and things may break.\n";
$write .= "if ( ! function_exists( 'wc_admin_get_feature_config' ) ) {\n";
$write .= "\tfunction wc_admin_get_feature_config() {\n";
$write .= "\t\treturn array(\n";
foreach ( $config->features as $feature => $bool ) {
	$write .= "\t\t\t'{$feature}' => " . ( $bool ? 'true' : 'false' ) . ",\n";
}
$write .= "\t\t);\n";
$write .= "\t}\n";
$write .= "}\n";

$config_file = fopen( 'includes/feature-config.php', 'w' );

fwrite( $config_file, $write );
fclose( $config_file );