While you cannot safely download the full Photoshop application from GitHub, the platform does host legitimate and add-ons related to Photoshop:
Portablizers: Scripts designed to make a legally owned version of Photoshop portable. github photoshop download windows
Configuration Scripts: Tools to optimize Windows for creative software. While you cannot safely download the full Photoshop
Download the Creative Cloud Desktop App (a small installer). github photoshop download windows