Both store modules are rewritten from a protocol-level spec: new Rust engines behind a small JNI surface (nativeCall/nativeInstall) and thin Kotlin facades, with the launcher's own user agent.
Epic: sign-in carries over, library, manifest download with byte-exact verification, assembly, uninstall, launch arguments, achievements.
Amazon: sign-in carries over, library, manifest download with per-file hash checks, path checks, executable detection from fuel.json, uninstall.
On-disk install layout is unchanged, so existing installs keep working.
Store game pages now take controller focus on their lead hero action (Install, Uninstall, Pause, Resume, Get, Buy), fall back to Back, and keep D-pad focus inside the page while it covers the library.
Space checks before Epic, GOG and Amazon installs (measured zero vs unknown), clear failure reasons with retry/clear, resume-aware checks, and safe per-file replacement so a failed or cancelled update never breaks an installed game.
Epic installs stream chunks straight into staged files in parallel (most bytes written once, a small budgeted cache for shared chunks, about 1x game size instead of 2x), pace updates by free space, and keep the lookahead, batch and bounded Java writers as hidden alternatives.
Co-authored-by: Juan Marti Mercado <juanma@microsoft.com>
Co-authored-by: The412Banner <the412banner@users.noreply.github.com>
Kurt Himebauch