libsixel-dev - 1.8.2-1+deb10u1 main

SIXEL is one of image formats for printer and terminal imaging
introduced by Digital Equipment Corp. (DEC). Its data scheme is
represented as a terminal-friendly escape sequence.
So if you want to view a SIXEL image file, all you have to do
is "cat" it to your terminal.
.
The package is for development.