Using a bluetooth dongle, USB ID 0bda:8771, error message as follows:

   [18523.098409] Bluetooth: hci0: RTL: rtl: examining hci_ver=0a hci_rev=000b
lmp_ver=0a lmp_subver=8761
   [18523.101396] Bluetooth: hci0: RTL: rom_version status=0 version=1
   [18523.101398] Bluetooth: hci0: RTL: rtl: loading rtl_bt/rtl8761b_fw.bin
   [18523.138519] bluetooth hci0: Direct firmware load for
rtl_bt/rtl8761b_fw.bin failed with error -2
   [18523.138521] Bluetooth: hci0: RTL: firmware file rtl_bt/rtl8761b_fw.bin
not found

I procured myself said missing binary blob from the manufacturer's website,
installed it and it appears to be working or at any rate to be detected
properly.

What confuses me is that not even
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/rtl_bt
contains that file and yet the module supports it.
Perhaps it's not distributable? Or did I miss the correct package to install?

Am I barking at the wrong tree here? Should I take this upstream? If so, to
whom?