The purpose of this legislation, known as the Sunset Chevron Act, is to establish a process for ending certain federal rules that have been upheld in court based on a legal principle called Chevron deference. This principle allows courts to defer to government agencies' interpretations of laws they administer, as long as those interpretations are reasonable. The Act aims to create a system where these rules will automatically expire after a set period, promoting accountability and ensuring that rules remain relevant and effective.