My Drupal 8.3 system (NOT the Acquia version), Update feature constantly tries to use .gzip s the type for downloading updates, but that doesn't work on Windows. I know I can download by hand and install that way, but it is slow and painful. Drush is doing the same. I have looked through LOTS of php and js code in the Drupal Core and can't find out how Drupal or Drush is supposed to find out what kind of system I'm using. I posted this as a problem a year ago on the Drupal forums, but no one has had any clues. Have I missed setting a value in settings.php? Or somewhere else?