This field test was against Next.js. The issue was Next.js #94450: https://github.com/vercel/next.js/issues/94450 The reported problem involved production browser source maps when React Compiler and Turbopack were involved. The visible symptom was that the final browser source map could expose transformed compiler output instead of preserving the original client source content. That matters because source maps are not just debugging extras. They are provenance artifacts. They tell the developer