This is WinDebloater by crazycheetah42. It is a script written in Python which uses PowerShell's Get-AppxPackage and Remove-AppxPackage cmdlets to remove bloatware from a specific list.
It is available as an executable which was generated through PyInstaller, which you can access through the Releases page. Make sure you run it as an Administrator, otherwise you will see lots of errors. You can also download it through PowerShell with BITS: Start-BitsTransfer https://github.com/crazycheetah42/WinDebloater/releases/download/v1.1.0/WinDebloater_v1.1.0.zip
It uses the subprocess module, which is built into Python to execute powershell with a list of commands. For example, the first command the script runs is 'Get-AppxPackage Microsoft.Microsoft3DViewer | Remove-AppxPackage'. The subprocess module will execute "powershell -Command Get-AppxPackage Microsoft.Microsoft3DViewer | Remove-AppxPackage", making it easy to remove bloatware without leaving the main script.