Thanks for mentioning {X,Y,Z}modem. I think folks forget that it still has modern uses.
(We used back in the day to move files between PDP11s and PCs - it was the original “anything to anything” file transfer program)
yes and also X/Ymodem, see source code: https://elixir.bootlin.com/u-boot/latest/source/common/xyzMo...
extremely useful feature (I used xmodem in the past, if I remember well)