The Bureau of the Fiscal Service is a sleepy part of the Treasury Department. It’s also where, sources say, a 25-year-old engineer tied to Elon Musk has admin privileges over the code that controls Social Security payments, tax returns, and more.The Bureau of the Fiscal Service is a sleepy part of the Treasury Department. It’s also where, sources say, a 25-year-old engineer tied to Elon Musk has admin privileges over the code that controls Social Security payments, tax returns, and more.