The chant “Khaybar, Khaybar ya yahud” celebrates Muslim victory over the Jews, as this article from the Jerusalem Post in 2013 explains:

Arab TV satellite channels are airing a series this year called Khaybar, referring to the Muslim massacre of the Jews of the town of that name in northwestern Arabia in 628 CE.

After the attack, some Muslims, including Muhammad, took surviving women as wives.

The Muslim conquerors charged the Jews a 50 percent tax on their crops and in 637, after Muhammad’s death, the Caliph Omar expelled the remaining Jews from Khaybar.

In Islamic tradition, the chant “Khaybar Khaybar, ya yahud, Jaish Muhammad, sa yahud,” which means, “Jews, remember Khaybar, the army of Muhammad is returning,” is used as a battle cry when attacking Jews or Israelis.

That was part of the chant at an anti-Israel rally in Miami, via Israel Matzav, who states that the rally was sponsored by CAIR and the National Lawyers Guild, among others (video by Danielle Avel):

I take them at their word, just like I take the anti-Semitic protesters in Paris, Berlin, Frankfurt, Boston and elsewhere at their word.

Miami anti Israel protest Khaybar ya Yahud