How do I perform a hard refresh in Safari?

It is not clear whether Safari truly distinguishes between a soft and hard refresh.  However, on MacOS, holding down the Option key while clicking the refresh button (with a text balloon of "Reload the current page.") appears to perform a hard refresh.  Though the refresh button can be pressed with the Shift key also depressed, this combination appears to be a soft refresh in our testing.  On Windows, much the same appears to be the case, with the Alt key taking the place of the Option key.

• What is a hard refresh?

• Web Browsers Safari