Debian Installer Bookworm RC 4 was released this Saturday to encourage more last-minute testing now being about two weeks away from the Debian 12.0 debut. There are some last minute UI tweaks to the Debian installer, support for multiple initrd parameters with its GRUB2 integration, support for LVM-on-LUKS-on-RAID setup via a new "crypto-lvm" keyword, making sure dosfstools is installed if a FAT EFI System Partition (ESP) is present, and various other last minute fixes.
More details on the Debian Installer Bookworm RC 4 release via the Debian development announcement list .