URE sends POST request via JavaScript here using predefined URL from ure_data.page_url property.

jQuery.ure_postGo(ure_data.page_url, {action: 'caps-readable', object: ure_obj, user_id: user_id, ure_nonce: ure_data.wp_nonce});

It’s defined at user-role-editor-pro/includes/classes/user-role-editor.php, line #733. If look deeper, URE takes URL from the URE_WP_ADMIN_URL PHP constant, which is defined at user-role-editor-pro/includes/define-constants.php, as:

define( 'URE_WP_ADMIN_URL', admin_url() );

Thus, URE uses here WordPress API admin_url() function in order to get admin URL. It does not use directly ‘wp-admin’ in this case. If some plugin replaces WordPress default path with a custom one, it should make it for WordPress API too, using appropriate filter, like ‘admin_url’.