The Markup, now a part of CalMatters, uses investigative reporting, data analysis, and software engineering to challenge technology to serve the public good. Sign up for Klaxon, a newsletter that delivers our stories and tools directly to your inbox. Data brokers are required by California law to provide ways for consumers to request their data be deleted. But good luck finding them. More than 30 of the companies, which collect and sell consumers’ personal information, hid their deletion instruc...