Dead firmware link on "DFU Programming 8U2" page

PieterP:
The new link should be ArduinoCore-avr/firmwares/atmegaxxu2/arduino-usbserial at master · arduino/ArduinoCore-avr · GitHub

Thanks for reporting this! I have opened an issue report in the bug tracker requesting this to be fixed, along with a bunch of other minor issues on that page:

If anyone has any additional suggestions for improvements to that page let me know and I'll update the issue.

PieterP:
The file names should probably be changed as well, since all modern Arduinos use the ATmega16U2, not the ATmega8U2.

Which filenames?