He shares old illustrations of Ohlone men, gliding along the water in long, sporty boats made of reeds, that show off the bay as it was before colonization — lush and nurtured. When Mr. Medina refers to Berkeley, he calls it by its old name, xucyun.

Mr. Medina is charming, addressing the dining room in a powerful oratorical style. He speaks loudly, slowly, with purpose. And he’s got jokes. “They weren’t just hunters and gatherers,” Mr. Medina said of his ancestors one night, pushing back against the stereotypes he heard as a child. “They ate the most bougie food imaginable!”

The dinner table might seem like an odd place for a lecture, but Mr. Medina and Mr. Trevino don’t run an ordinary restaurant. Cafe Ohlone is part of the nonprofit organization they founded called Mak-’amham — meaning “our food” in Chochenyo, the native language of the East Bay — that also hosts cultural events for the Ohlone community.

You enter the popup through the quiet, pleasantly cluttered aisles of University Press Books. Seating is communal, outdoors, at large tables that hold about 40 people comfortably. Before dinner, Mr. Medina and Mr. Trevino carefully introduce every staff member working to pour tea, serve food and clear the tables. Many are relatives or friends.

And before diners take their first bites, Mr. Medina says a prayer of gratitude in Chochenyo. Mr. Trevino, 28, follows with a prayer in his community’s language, Rumsen.

My first thought was an obvious one: California cuisine wasn’t born in the 20th century. It wasn’t an invention of 1970s Berkeley or 1980s Yountville. It wasn’t created by chefs in restaurant kitchens. It thrived, in pockets across the region, long before it was identified as a movement in a food magazine.

Mr. Medina and Mr. Trevino interviewed their elders, and studied Ohlone techniques and recipes that were written down in the 1920s and ’30s. What they found was an earlier incarnation of California cuisine, fittingly fresh and local, farmed and foraged, diverse and polished.