When a privacy app publishes its source code, many users assume that's sufficient to trust the binary they download. It isn't. The gap between source code and running software is a build pipeline — and that pipeline is exactly where sophisticated attackers insert themselves. Reproducible builds close that gap. Open source software has a trust problem that open source alone doesn't solve. You can publish every line of code on GitHub and still distribute a binary that contains code nobody reviewed. The build system — the servers, scripts, compilers, and toolchains that turn source into executable — sits between the audited code and the running program. Reproducible builds are a technique that lets anyone independently verify a binary was compiled from specific source code, without trusting the developer's build infrastructure.…