"cartridge" (disk image) based pragmatic security focused distro.

disk images for a variety of use cases sit in /img/ on the largest blk device.

you choose which one gets mounted as root on boot.

a simple wrapper for qemu allows you boot the other images as virtual machines.

this allows testing of kernel and all dependencies. if you 

helper scripts allow you to promote the contents of the image to the main kernel and initramdisk to the primary boot slot.

this effectively gives you some of the immutability features of nix, with the flexibility of ubuntu/debian.

unique applications:
QEMU virtualization tooling. helper functions with optional persistence.

DNS and application level firewalls.