Who were the aliens referred to in the alien and sedition acts?

The alien and sedition acts were the four controversial laws passed by Federalists in Congress. They argued that these laws were needed to protect the country from troublemakers like Citizen Genet. In fact, the real purpose of these acts was to make life difficult for the Federalists' rivals, the Republicans.

Added: When used in an Immigration and citizenship context the term "alien" refers to any non-nativeborn foreigner.