storefront_html_tag_schema() was deprecated in Storefront 2.0.2, but it looks like function was dropped completely on the ww.wp.xz.cn-hosted version of the plugin. This causes a fatal error on child themes. I notice that the latest version of Storefront (2.0.3) has removed the function call from the html tag altogether, so you can probably just remove it from html in any child themes and it’ll be fine.
Curiously, the Github-hosted version of Storefront deprecates the function nicely, but the ww.wp.xz.cn version simply removes the function definition. Some sort of discrepancy?
