Is this a kernel replacement, as in I could run Manjaro Gnome, and just load the Asahi Kernel and it all Just Works?
Or will Asahi Linux need to be a full distro of its own, in order to be useful?
m1n1 is our bootloader, which once installed will present a standard (ish) U-Boot/UEFI boot environment. From there you will be able to boot any distro or USB installer, in principle, once the changes trickle upstream.
Our installer will install m1n1 and then give you the choice of also installing a distro image. We'll be providing our own based on Arch Linux ARM, but we're open to other distros providing images so we can add them to the list. We already have interest from Fedora, for example.
So we expect that people who want to run Linux (or in fact openbsd or anything else) on these Macs will first use our bootloader installer, then either pick one of the built-in images or use their own USB installation media from whatever distro.
That said, all components will be upstreamed into their respective projects such that other distributions should eventually be able to add support for Apple's line of desktop computers with Apple Silicon.
[1] https://asahilinux.org/about/#is-this-a-linux-distribution