"duplicate cell" button

[Syndesi]

Hi,
it would be awesome if I could simply duplicate a cell and its content, so that I can experiment and prototype easier :D

[liquidcarbon]

Sometimes I also wish for "duplicate" button but it might bring trouble of redefining same variables.

Curious if it's absent by design.

A few lines may be duplicated within a cell and then split at the cursor with a keyboard shortcut.