Reproducible builds can have some unexpected benefits. For example, a package build machine could track compiled files that have changed since it compiled an older version of the software, and store them at the start of the archive when zipping the installable files into package. Then when the user’s package manager updates to the newer package, it only has to download enough of it to extract all the files that have changed between versions, thus saving time and bandwidth. Software that builds reproducibly will have fewer gratuitous changes (dates, etc), thus making this process work better.<p>In fact, OpenBSD’s and PC-BSD’s package managers do this. It’s briefly touched on in the last slide of this talk: <a href="http:&#x2F;&#x2F;www.openbsd.org&#x2F;papers&#x2F;eurobsdcon2015-packages.pdf" rel="nofollow">http:&#x2F;&#x2F;www.openbsd.org&#x2F;papers&#x2F;eurobsdcon2015-packages.pdf</a>