Debian developers have been working on Reproducible Builds for a number of years[0]. Currently the Debian amd64 distribution is ~93.7% reproducible[1]. It's possible that Debian amd64 systems will be fully reproducible in Stretch+1 (~2-3 years).
The Debian wiki page appears to be about reproducible builds for packages.
The NetBSD wiki entry is about progress on reproducible builds for tools, kernel and userland.
As for packages, reproducible builds under pkgsrc is still a WIP.
My use of third party binary packages and pkgsrc is minimal but I am continually building custom kernels and crunched binaries with build.sh and I do make use of the binary userlands from releng.
For me at least, having reproducible builds for these alone is quite useful.
I should have guessed. I use their libc6 package for q)k) under /emul/linux and in the past the live.debian.org images occasionally but that is about as much as I know about Debian. Apologies for my ignorance.
93% of the distribution could be enough for almost everybody or for nearly nobody if some core packages are not reproducible yet. Is there any data on that? Maybe using the Debian popcon data?
[0] https://wiki.debian.org/ReproducibleBuilds
[1] https://tests.reproducible-builds.org/debian/reproducible.ht...