From the debian-boot mailing list:
* pkgsel:
- Ensure tasksel is installed, regardless of its priority.
- Add preseedable pkgsel/run_tasksel debconf template, making it
possible (by setting it to false) to skip tasksel entirely
(installation and prompt), while still benefiting from other
pkgsel features.
* preseed:
- Update auto-install/defaultroot, replacing buster with bullseye.
Has loads of scripts and conditional actions going on, and is intended to work either from a remote server, or from a directory that d-i can see: hands.com/d-i/
he initrd of d-i can indeed be extended / appended. And in the "appendix" goes the desired extras. Then
d-i preseed/early_commands /myextras/early_script
