Mumford & Sons perform at Chase Center in San Francisco on Sept. 19, 2019. Photos: Joaquin Cabello. SAN FRANCISCO — One year, they were playing Popscene to a couple hundred people. Fast forward a decade, and they were being handed the John Steinbeck Award by two of the Bay Area’s premier…

Mumford and Sons perform at the Greek Theatre in Berkeley on May 30, 2013. Roman Gokhman/STAFF. BERKELEY — “How many of you are students?” Marcus Mumford surveyed the packed crowd at UC Berkeley’s Greek Theatre Thursday night, the second of three consecutive sell-outs for London folk-rockers Mumford & Sons. “How…