The Ramp test starts with 5 minutes at 46% of FTP. It adds 6% every minute. Assuming your FTP is near the one set at the test, you get 10 total minutes before passing 82% effort. It is 13 minutes before you hit the set FTP (100%).
That is considered enough warm-up in some cases, and more so since the effort here is a steady, but gradual increase.
As they have said in the past, you can add a warm-up if you want. But you must do that same one before each Ramp test to maintain consistency of results.