import type { CustomSyntaxChecker } from '../types.js';
/**
 * Validates a serialized permissions policy string according to the W3C specification.
 *
 * @see https://w3c.github.io/webappsec-permissions-policy/#serialized-permissions-policy
 *
 * > Policy Directives in HTML attributes are represented as their
 * > ASCII serialization, with the following ABNF:
 * > ```abnf
 * > serialized-permissions-policy = serialized-policy-directive *(";" serialized-policy-directive)
 * > serialized-policy-directive = feature-identifier RWS allow-list
 * > feature-identifier = 1*( ALPHA / DIGIT / "-")
 * > allow-list = allow-list-value *(RWS allow-list-value)
 * > allow-list-value = serialized-origin / "*" / "'self'" / "'src'" / "'none'"
 * > ```
 *
 * But change below according to current supported:
 *
 * ```abnf
 * serialized-policy-directive = feature-identifier [RWS allow-list]
 * ```
 *
 * `allow-list` is optional.
 */
export declare const checkSerializedPermissionsPolicy: CustomSyntaxChecker;