The tukaani github repos are gone, is there a mirror somewhere?
Though unfortunately (or I guess for most use-cases fortunately) you can’t find the malicious m4/build-to-host.m4 file on there afaik. The best way to find that now, should you really want to, is by looking through the commit history of the salsa.debian.org/debian/xz-utils repository which is, as far as I understand it, the repository that the debian packages are built from and consequently also what the compromised packages were built from.
In a nutshell you say…
Any additional information been found on the user?
as long as you’re up to date on everything here: https://boehs.org/node/everything-i-know-about-the-xz-backdoor
the only additional thing i’ve seen noted is a possibilty that they were using Arch based on investigation of the tarball that they provided to distro maintainers
