&gt; <i>a magic wand that makes source-to-source changes on a 100MLOC codebase trivial is pure fantasy</i><p>Actually, I have a slightly unrelated question: what <i>are</i> the issues that affect 100MLOC codebases that aren&#x27;t so important for smaller projects? This is something people sometimes bring up, but I&#x27;m not too sure what exactly they mean by it.