Tools for etching leather?
Based on the appearance of the tool (the thick shaft and the guard around it), the person in the video is drawing on the leather using heat, rather than 'cold' etching, carving, or engraving the leather. This is known as pyrography.
The tool used here is called a 'solid-point burner'.
This tool is attached to a power source, often (and preferably) has temperature controls, and produces heat leading to a tip that can often be changed for improved surface control (see upper tool in image below).
A common alternative, which is quicker to work with and allows for more control over temperatures and surface contact, is the 'wire-nib burner' (see lower tool in image below).

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