Source map

A source map is a companion file that maps compiled JavaScript back to the code you wrote. Browsers use it so a stack trace points at a real line. It is a build tool, not a secret, and in development it is exactly what you want.

Published to production, it hands a stranger your file names, your comments, your route structure and every string you left in the code. None of that is a breach on its own. All of it makes finding the real problem faster.

A check requests your bundles and looks for the map reference and whether the map itself answers. That is finding O3, and the evidence line names the file. The fix is a build setting, usually one line, and it is the cheapest item on most results.

• Source maps are published next to the app code

No incident in the library maps to this one yet.