> "I'd still absolutely love to see the code behind this feature."
Windows PowerShell has a cmdlet ConvertFrom-String which "supports automatically-generated, example-driven parsing based on the FlashExtract, research work by Microsoft Research."[1]. Then when they open-sourced Powershell, that was one of the cmdlets which did not come over and is no longer supported, so no way to see the source code there, sadly.
(Video [2] shows that FlashFill and FlashExtract and Excel / PowerShell uses are related, and he says it generates many possible programs which fit the given examples, and uses 'machine learning based ranking techniques' to choose which one fits best).
[1] https://docs.microsoft.com/en-us/powershell/module/microsoft...