Kache is a build cache system for Rust and C/C++ that acts as a transparent compiler wrapper (via RUSTC_WRAPPER or as a drop-in for cc/c++). It caches compilation artifacts using content-addressed storage with Blake3 hashing, enabling zero-copy restoration via reflinks/hardlinks/copies. The system features a daemon for asynchronous remote operations (S3/filesystem), a CLI/TUI for cache management and monitoring, and advanced capabilities like dependency chain analysis for cache misses, extra inputs for user-defined cache key influences, and predictive prefetching. Architecture-wise, it consists of a compiler wrapper core, a background daemon, a remote planning service (kache-service), and extensive testing/benchmarking harnesses. The code demonstrates strong craftsmanship in areas like cache key normalization, zero-copy restoration strategies, and compiler abstraction patterns.