It's in experimental only, not unstable or testing. That said I'm surprised it hasn't even propmpted discussion on debian-devel (sans [0]). I would've thought that at least enough Debian developers run experimental to have noticed and raise the issue, but no. I thought about starting a thread myself but couldn't be bothered.

[0] https://lists.debian.org/debian-devel/2026/04/msg00004.html

Considering how Ubuntu seems to influence Debian development, this is only slightly surprising.

See: https://lists.debian.org/deity/2025/10/msg00071.html - Hard Rust requirements from May onward - by a Core Ubuntu Developer