The safe money bet is that someone at Anthropic trusted Claude to write that code. El oh el.

https://arstechnica.com/ai/2026/03/entire-claude-code-cli-source-code-leaks-thanks-to-exposed-map-file/

Entire Claude Code CLI source code leaks thanks to exposed map file

512,000 lines of code that competitors and hobbyists will be studying for weeks.

Ars Technica