I keep thinking I can replace this add-on. Unfortunately, this is not true. Once you have grown accustomed to the ease and power of this add-on, there is no other add-on that can possibly replace it.

Doesn't work on Manjaro KDE with FF 122.0.1

Edit: Works now after reassigning the shortcut because alt+shift+d was already in use by another extension (Dark Reader). Would be five stars if it was possible to toggle whether to switch to the duplicated tab.

Edit2: FIVE STARS AND A SEAL OF APPROVAL!

(There's a bug where the "Open new tabs in the background" feature doesn't seem to work with "New tab to the right" no matter what shortcut I try to assign to it)

Does just about it.

Nice and fast I used ctrl+shift+v. almost every single shortcut is already taken so youhave to be creative.

go into the settings tab to change keys

Amazing, I love it.

If you need ideas for keybinds, I suggest Alt-T to duplicate tab, Alt-N to pop tab to a new window.

To me the 'Pop tabs to a new window' is as important, if not more important than the 'Duplicate tab' shortcut, so the name of the extension is unfortunately a bit misleading..

It works for what I wanted it to — duplicating tabs with a hotkey — so I am completely satisfied. And, on top of that, it also supports a hotkey for another great feature: new tab to the right. This extension is amazing, I love it.

Sadly, it's not working for me.
Pressing [Alt]+[Shift]+D just opens the menu bar as if I was just pressing [Alt].

(using Firefox 99.0.1 on Windows 10)

I think it has something to do with localization. I use a german translation, where the "File" menu is called "Datei". So [Alt]+D opens that Dropdown for me ignoring [Shift].

It says in the description, that "Shortcut is configurable.", but I cannot find where.
//Update: I found it, thanks to the Screenshot. I'm just stupid. Sorry.

I changed it to [Alt]+[Shift]+K in manifest-json and created the extension myself for self-distribution.