Per microsoft/terminal#217 - originally created when I wanted to be able to Ctrl-C things like yarn and gulp without being confirmed - Microsoft strongly recommend against creating new .cmd files.

From various Microsoft staff (and echoed repeatedly in microsoft/terminal#217)

If you're writing Windows Command-Line scripts today, they should be PowerShell scripts wherever possible

Moving yarn.cmd and yarnpkg.cmd (which are tiny) to .ps1 would allow users to cancel them without having a silly confirmation prompot, and probably also avoid other unforeseen drama due to cmd being unmaintained.

Happy to send a PR, just wanted to discuss first.