For AI agents: the complete documentation index is available at /next/zh/llms.txt, the full documentation bundle is available at /next/zh/llms-full.txt, and this page is available as Markdown at /next/zh/api/lynx-testing-environment/TypeAlias.PickUnderscoreKeys.md.

type PickUnderscoreKeys<T>: Pick<T, FilterUnderscoreKeys<T>>;