Filters whether a "hard" rewrite rule flush should be performed when requested.
$hardboolwp-includes/class-wp-rewrite.php:1899WP_Rewrite::flush_rules() * A "hard" flush updates .htaccess (Apache) or web.config (IIS). * * @since 3.7.0 * * @param bool $hard Whether to flush rewrite rules "hard". Default true. */ if ( ! $hard || ! apply_filters( 'flush_rewrite_rules_hard', true ) ) { return; } if ( function_exists( 'save_mod_rewrite_rules' ) ) { save_mod_rewrite_rules(); } if ( function_exists( 'iis7_save_url_rewrite_rules' ) ) {Introduced in 3.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.