Filtered highlights from #664:

• Cargo: epage’s A Vision for Cargo outlines future direction; Cargo also gained profile-debug support, build-started JSON messages with run_id, more trim-paths work, and resolver fixes.
• Compiler: LLVM 23 brought broad compile-time, runtime, bootstrap-time, and artifact-size improvements. Polonius alpha on nightly currently costs about 3% in performance, with mitigation still under investigation.
• Language: There is a call for testing restrictions on trait implementability and field mutability; cyclic trait solving and the next solver are prominent design topics.
• Systems/embedded: Rust Coreutils was covered as a modern rebuild of Unix foundations; a chip-agnostic bare-metal architecture and a universal hardware-in-the-loop HAL test suite are also highlighted.
• Other useful reads: a Rust rewrite performance reality check, TLS benchmark results across four crypto libraries, and git-cache-proxy, a read-only cache for Git clones over slow networks.

The issue also includes literator as crate of the week and RFC approvals for hints.min-opt-level and extern "custom".