OpenWrt - reproducible wireless freedom?

Reproducible builds enable anyone to reproduce bit by bit identical binary packages from a given source, so that anyone can verify that a given binary derived from the source it was said to be derived. There is more information about reproducible builds on the Debian wiki and on https://reproducible-builds.org. These pages explain in more depth why this is useful, what common issues exist and which workarounds and solutions are known.

Reproducible OpenWrt is an effort to apply this to OpenWrt. Thus each OpenWrt target is build twice, with a few variations added and then the resulting images and packages from the two builds are compared using diffoscope. OpenWrt generates many different types of raw .bin files, and diffoscope does not know how to parse these. Thus the resulting diffoscope output is not nearly as clear as it could be - hopefully this limitation will be overcome eventually, but in the meanwhile the input components (uImage kernel file, rootfs.tar.gz, and/or rootfs squashfs) can be inspected. Also please note that the toolchain is not varied at all as the rebuild happens on exactly the same system. More variations are expected to be seen in the wild.

There is a weekly run jenkins job to test the master branch of OpenWrt.git. The jenkins job is running reproducible_openwrt.sh in a Debian environment and this script is solely responsible for creating this page. Feel invited to join #reproducible-builds (on irc.oftc.net) to request job runs whenever sensible. Patches and other feedback are very much appreciated - if you want to help, please start by looking at the ToDo list for OpenWrt, you might find something easy to contribute.
Thanks to IONOS for donating the virtual machines this is running on!