Hey, Reto!

I believe so, there is a debian package called raspi-firmware. See https://salsa.debian.org/raspi-team/image-specs/-/blob/master/raspi_master.yaml?ref_type=heads#L83

Sidenote: since recording this, I've learned that the graphical app Raspberry Pi Imager (https://www.raspberrypi.com/news/raspberry-pi-imager-imaging-utility/) can do some of the things I talked about here, such as adding an ssh key to the authorized_keys file.