Plan is to extend badge internals with Z80 core adding ZX-Spectrum and PetersPlus Sprinter graphics to run existing software written for those retro computers and downloaded from the Internet directly to the badge...
Pull request also has a program that showing this image:
Image itself is 16-color 736x288 and program takes 720x288 part of it and "squeezes" it into screen 480-pixel width using generated 256-color palette, that helps to represent THREE 16-color pixels as TWO 256-color pixels using this formula for every color channel NEWCOLOR = (C1 + 0.5 * C2)/1.5 (in more sophisticated way for speed).
And this also fixes HDMI output (that looks a little worse than screen on the badge because of upscaling):