May 2025 performance summary for tweag/topiary: Delivered Selective Language Grammar Prefetch feature, adding an optional language argument to the prefetch command. When provided, only the specified language grammar is loaded; when omitted, the command retains its existing behavior of prefetching all configured languages, preserving backward compatibility. The change improves efficiency and responsiveness for language-specific workflows by avoiding unnecessary grammar loads. Implemented via config changes and a single feature commit. No major bugs reported this month; overall impact includes faster prefetch operations, reduced resource usage, and clearer language-specific pipelines. Key tech: CLI/config design, feature flag-like behavior, and commit traceability.