With the arrival of kernel 5.4.0-2-amd64 now there are three missing firmware files:
update-initramfs: Generating /boot/initrd.img-5.4.0-2-amd64 W: Possible missing firmware /lib/firmware/i915/icl_dmc_ver1_07.bin for module i915 W: Possible missing firmware /lib/firmware/i915/tgl_dmc_ver2_04.bin for module i915 W: Possible missing firmware /lib/firmware/i915/bxt_huc_ver01_8_2893.bin for module i915 All of them are in the source package (???)