[dsr_]

It's for firmware for network devices, especially wifi.

An annoying number of Debian installs fail on laptops because the wifi needs firmware and people expect it to work. You can choose to enable non-free after install, but the installer doesn't have that as a direct option.

Prior to this, an alternative installer was available that had the firmware in it... but it was not well-publicized, and was not the default or even available from the same page as the default.

If you install with non-free firmware, it will continue to be installed afterwards.

[zozbot234]

Some graphics and sound hardware also requires firmware these days, and working sound is important for accessibility.