This should not come as big news to anyone, as we said last week that Panda hasn't fundamentally changed and it still works the same way.
So to visualize this... Google will crawl the web, pick up on signals and assign your site a Panda score (unlike RankBrain which doesn't get a score). After it gets a new score for your site, it will push that score to your pages slowly over months - just like it did with Panda 4.2.
It takes "months" to roll out even today, Gary Illyes re-confirmed.
Here are some tweets from the session:
You can watch the live 1 hour video on Search Engine Land's Facebook page.
Forum discussion at Twitter.