/** Shown unless the visitor hid them. Absent means no preference, and no preference means show. */
export declare const readDebugPreference: (name: string) => boolean;
/** JSON, because that is the shape `useStorage` wrote for as long as this was a `useStorage` value, and a cookie
 *  written before this change still has to read back the same. */
export declare const writeDebugPreference: (name: string, shown: boolean) => void;