This is a custom-designed rack mount bracket for the Home Assistant Yellow, specifically made to fit this 19-zoll rack rail:
https://www.amazon.de/dp/B000T9L9L6?ref_=ppx_hzod_title_dt_b_fed_asin_title_0_0
(DAP 2 HE Rackblende f. Modulsystem 10 Segmente MP-1)

The bracket is designed for easy sliding installation, allowing you to securely mount the Home Assistant Yellow without any modifications. It also supports the use of the original screws, ensuring a stable and reliable fit.

Perfect for keeping your Home Assistant setup organized in a rack environment!