The final line of a law is usually how long it's intended to exist, like an expiration date for milk.

The Alien Friends Act only lasted until 1800, and the Sedition Act only lasted until 1801. When Jefferson took office, he was content to run out the clock on these. The Naturalization Act didn't include an expiration date, so it had to be repealed with a whole other law. The creatively-named Naturalization Act of 1802 did the job. (Source)

And uh, the Alien Enemies Act was just…ignored. It's alive and kicking today.