@vuepress-reco/style-default/lib/client/components/SidebarChild.d.ts

It is default type of vuepress-theme-reco.

import type { FunctionalComponent } from 'vue';
import type { ResolvedSidebarItem } from '../../types';
export declare const SidebarChild: FunctionalComponent<{
    item: ResolvedSidebarItem;
    depth?: number;
}>;