SeedSigner OS reproducible build allows creation of the image to be compiled and assembled deterministically. This makes it possible for multiple people to compile the same source code into identical binaries. This also means SeedSigner the person (or any other SeedSigner contributors) don't need to be solely trusted for the image that most people run on thier SeedSigner. This trust can be distributed through others attesting they too can produce the same image byte for byte. Also for those who compile the image themselves, they have a way to verify the image produced is identical to the one released.
Clone the SeedSigner OS repo from github. Do this with a recursive clone to pull the buildroot submodule at the same time. By default this will create a directory in the current working directory named seedsigner-os.