Katie Heaney, at The Cut, explains:

Recently, I saw a conversation between a few women I follow on Twitter about Fiona Apple, who was profiled by Vulture last month. In the course of her interview, Apple mentions that she’s stopped drinking, but has started smoking more weed instead: “Alcohol helped me for a while, but I don’t drink anymore,” she says. “Now it’s just pot, pot, pot.” This was the part of the interview the women were discussing. “Fiona Apple: Cali sober??” one wrote.

The term “Cali sober” here refers to people who don’t drink but do smoke weed, though internet definitions vary slightly: Urban Dictionary says it means people who drink and smoke weed but don’t do other drugs; an essay by journalist Michelle Lhooq uses it to refer to her decision to smoke weed and do psychedelics, but not drink. While the term is new to me, the behavior it describes is not. …

RTWT