Filtered highlights from This Week in Rust 663:

• Official: Polonius borrow-checker alpha is available on nightly; the Rust project adopted an LLM policy and published a funding update.
• Tooling/systems: FalkorDB is being rewritten in Rust; there is a useful Firecracker internals overview for sandboxing untrusted code and AI agents; WebRTC 0.20 adds a runtime-agnostic, sans-I/O core.
• Cargo/compiler: unchanged lockfiles can avoid reparsing, and the new build-directory layout is advancing on nightly; July compiler triage reports a net 2.7% primary-instruction improvement.
• Embedded: STM32F103 Rust bring-up and new Rust MEMS-driver work are highlighted.
• Crate of the week: index_type, for strongly typed collection indices.

The issue reports 630 merged Rust PRs, with no RFCs approved this week.