Apple Finally Adds Duplicating a Tab in Safari 13.1
2020, Apr 21
In Safari 13.1 Apple finally added built-in support for duplicating a tab. In the past, there were workarounds, but they were not ideal because they didn’t preserve the history of the tab. You couldn’t go back forward on the duplicated tab like you could in the source tab.
Unfortunately, there is no keyboard shortcut. You can create a keyboard shortcut in Keyboard preferences.