The Clone tab of the Webform allows Publishers to duplicate an entire Webform (the 'placeholder' as well as all the form components).
Update the Title before saving!
Be sure to update the title before you click Save, or the Webform will be saved as 'Clone of \[original Webform title here\]' (and the URL created accordingly).
Group Publisher role explicitly required
If you do not see the 'Clone' tab, make sure that you have the 'Group Publisher' role checked even if you are an Admin (this is a known bug).