Less seriously, The Magical Excel 97 Far East Language Build Screwdriver™ (https://devblogs.microsoft.com/oldnewthing/20191119-00/?p=103115 https://devblogs.mic

Less seriously, The Magical Excel 97 Far East Language Build Screwdriver™ (https://devblogs.microsoft.com/oldnewthing/20191119-00/?p=103115 https://devblogs.microsoft.com/oldnewthing/20191119-00/?p=10...) More seriously, as the article states, it is the configuration etc. of those build computers. The code is pre-cloud computing (where VMs to build stuff can be archived for pennies), and the build computers are likely gone given how old the component is.