Linux Firmware Notes
Some issues with non-free firmware blobs on Debian
ASpeed Technologies
The sudo dmseg command shows the warning Possible missing firmware /lib/firmware/ast_dp501_fw.bin for module ast. This relates to the ASpeed BMS VGA graphics microcode. The simple solution seems to be be to install the non-free microcode blob using sudo apt install firmware-ast.
It would seem that this warning can be ignored, however the warning will remain. The hardware or software? is reportedly end of life 2018, interesting as it is quite clear the related hardware was being sold much later than this.
Realtek
When reviewing the start log using sudo dmesg a number of warnings such as Possible missing firmware /lib/firmware/rtl_nic/rtl8125b-2.fw for module r8169 are observed. This related to the Realtek network card non-free binary blobs. And can be simply fixed using the command sudo apt install firmware-realtek and possible also sudo apt install firmware-misc-nonfree.
As these are warning only and the hardware apparently is operational that options is to accept the warning message and do nothing.