I think it's '[open-source] [hardware rendering]', not '[open-source hardware] [rendering]' - the key tidbit being the distinction between "software rendering"

I think it's '[open-source] [hardware rendering]', not '[open-source hardware] [rendering]' - the key tidbit being the distinction between "software rendering" and "hardware rendering" - the former is shorthand for rendering purely on the CPU, while the latter uses the graphics card for faster rendering speed.