I wasn't there because I knew there was a chance of violence. But I know a lot of people who were so I'll try to share their perspective.
My organization, ______, called for a protest and attempted shut-down of Milo Yiannapolous. We participated in a coalition with campus groups and Berkeley Antifa to organize a multipronged struggle against Milo and his predominantly neo-nazi cronies. Leading up to yesterday there were many organizing meetings and a long campaign including less radical groups trying to put pressure on the admin to cancel the event, to no avail, even as Milo's supporters attacked and even shot anti-fascist organizers on other campuses.
A few thousand folks answered the call, vastly outnumbering the people who were trying to hear Milo speak. Multiple police forces were dispatched in order to ensure the safety of the *literal nazis* who had come to network through the event.
Also present was a group of black bloc anarchists, you know, the face-covering smashy smashy folks who tend to escalate confrontations with cops and make large gatherings like this less safe and accessible to the broader masses of the working class.
The event was canceled almost immediately due to the size and militancy of the protesting group. But a lot of other things happened and it's not super clear in what order members of different groups attacked each other.*____*told me she saw a nazi with a bloody nose going around trying to provoke people into fist-fighting. At some point the black bloc folks (or maybe provocateurs, it's always hard to know) set fire to a generator and also launched fireworks at the cops which provoked some rubber bullets. Surprisingly my understanding is that the cops didn't start off by summarily pepper-spraying the entire crowd (maybe it's because their nazi friends were in the crowd, actually; the UC released a statement about brave campus cops "rescuing" individual targets of violence from the crowd, and I guarantee you those individuals were all nazis).
_____ -- my main source on these more detailed bits -- left the event around 7:30 at which point the protest was still going fairly strong but the right-wing element was getting more agitated. Walking home we heard dispersal orders from a police helicopter ringing all over Berkeley. I just woke up and don't know how the situation devolved later in the evening.
Hope this helps.