This week Bun published its internal Zig→Rust porting guide — a signal that the runtime is migrating core components from Zig to Rust. The HN thread hit 700+ points in 24 hours. The Rust move is a reasonable technical bet. Rust's ecosystem maturity, tooling, and contributor onboarding advantages at Bun's scale are real. But for teams running LLM workloads in production, the migration surfaces a question worth thinking about: what does it mean that your JavaScript runtime is now an Anthropic asset? Background: December 2025 Anthropic acquired Bun in December 2025. For most developers this was a minor footnote. For teams running AI pipelines, it quietly changed the vendor dependency structure. If you're using Bun as your JS runtime, Claude Code as your AI CLI, and Anthropic as your LLM provider, all three now share the same balance sheet. The Rust port doesn't change that — it makes Bun faster and easier to contribute to, but it doesn't change who owns it.…