So the firmware for a certain WiFi card is the same, no matter if you use Linux or Windows of MacOS? And it is provided by the manufacturer of the Hardware?
And some WiFi cards works out of the box with Debian? Is that because the manufacturers of those cards provided the source of their firmware or because open source alternatives have been written by somebody else?
firmware is specific to chipset and are binary blobs supplied by the manufacturer. ath9k-supported and generally realtek cards don't need firmware; theo de raadt noticed the culture difference between american vendors like intel and broadcom who leave the functionality to the firmware so they can be first to market, and chinese vendors like realtek who take their time to best fit customer needs
And some WiFi cards works out of the box with Debian? Is that because the manufacturers of those cards provided the source of their firmware or because open source alternatives have been written by somebody else?