In the middle of a Covid-19 lockdown packed with distance learning difficulties, teachers at the Schmalkalden Elementary School in Thuringia, Germany, learned that the digital tool they had been using didn’t meet the country’s strict data-privacy restrictions. “A parent at the school asked whether I could develop a program from scratch over the weekend,” said Mathias Wickenhagen, a 20-year-old programmer in the neighborhood. “And I did.”