HONG KONG/NEW YORK (Reuters) -Embattled developer China Evergrande Group has filed for bankruptcy protection in a U.S. court as part of one of the world's biggest debt restructuring exercises, as anxiety grows over China's worsening property crisis and a weakening economy. Once China's top-selling developer, Evergrande has become the poster child of the country's unprecedented debt crisis in the property sector, which accounts for roughly a quarter of the economy, after facing a liquidity crunch in mid-2021. The developer has sought protection under Chapter 15 of the U.S. bankruptcy code, which shields non-U.S. companies that are undergoing restructurings from creditors that hope to sue them or tie up assets in the United States.