tl;dr: Valve has open-sourced the design files for the Steam Machine's e-ink front display (dubbed "Inkterface") on their GitLab under an MIT license, since they won't be manufacturing it themselves. Builders will need parts like an Adafruit ESP32 Feather, an eInk breakout board, a 5.83" monochrome panel, and some screws and magnets to assemble one. Third parties like JSAUX have already indicated plans to sell pre-built versions.