The solution SimpleLauncher.sln and the two documented projects in depth. Related: 01 — Overview · 04 — Architecture

Dependency edges: SimpleLauncher → SimpleLauncher.Core; SimpleLauncher.Tests → SimpleLauncher; SimpleLauncher.Avalonia.Tests → SimpleLauncher.Avalonia; SimpleLauncher.Avalonia.Updater standalone (no compile reference — the Avalonia app publishes it and copies Updater.exe next to itself); SimpleLauncher.Avalonia references Core (via InternalsVisibleTo). SimpleLauncher.Avalonia.Tests targets net10.0 (not -windows) so it runs on Linux CI/WSL2 without the Windows desktop pack.

Key properties:

<TargetFramework>net10.0-windows</TargetFramework>
<OutputType>WinExe</OutputType>
<UseWPF>true</UseWPF>
<LangVersion>14</LangVersion>
<Nullable>enable</Nullable>
<RuntimeIdentifiers>win-x64;win-arm64</RuntimeIdentifiers>
<ApplicationManifest>app.manifest</ApplicationManifest>
<StartupObject>SimpleLauncher.App</StartupObject>
<AssemblyVersion>/<FileVersion>/<Version>5.8.4</Version>
<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
<RuntimeFrameworkVersion>10.0.2</RuntimeFrameworkVersion>
<SupportedOSPlatformVersion>7.0</SupportedOSPlatformVersion>

• Versioning: 5.8.4; kept consistent with Core, tests and app.manifest (VersionConsistencyTests enforces it).
• InternalsVisibleTo("SimpleLauncher.Tests") — tests reach internal members.
• Copy-to-output payloads (<None Update=... CopyToOutputDirectory>):
  • appsettings.json (Always), WhatsNew.md (PreserveNewest), mame.dat (Always), system images images\systems\*.png (Always), audio\*.mp3.
  • tools\* payloads: findromcover\, createbatchfilesforscummvmgames\, createbatchfilesforwindowsgames\, BatchConvertTo7z\, CreateBatchFilesForPS3Games\ (stale entries for ps3batchlaunchercreator\ remain in the csproj but have no folder on disk — see 11 — Bundled Tools), plus 7za binaries, system images, and more.
• Global usings: System.IO, System.Net.Http, Serilog.
• NoWarn: NU1903;CS0436.
• Startup object is SimpleLauncher.App (see 04 — Architecture).

Key properties: net10.0-windows, IsPackable=true, Nullable enabled, LangVersion 14, DebugType=embedded, version 5.8.4.

• InternalsVisibleTo: SimpleLauncher.Tests, SimpleLauncher, SimpleLauncher.New, SimpleLauncher.Avalonia, SimpleLauncher.New.Tests.
• Global usings: System.IO, System.Net.Http, Serilog — so every Core service takes a Serilog ILogger by convention.
• Packages: the same core set as the app (CommunityToolkit.Mvvm, MessagePack, Microsoft.Extensions., SharpCompress, NAudio, SharpDX, Serilog, Tomlyn, YamlDotNet, SourceGear.sqlite3, Meziantou.Analyzer) — no WPF/MahApps (it targets net10.0-windows because of DPAPI ProtectedData, System.Drawing-adjacent helpers, and Windows-specific services, but stays UI-agnostic). RetroAchievements hashing is not a package: all hash computation is delegated to the bundled tools\RetroAchievementsSharp\ CLI binaries (see 09 — RetroAchievements).
• Shared localization packs: Localization\strings.{lang}.json (18 languages, canonical strings.en.json) are the single source for both apps — both embed them in their assemblies (WPF pack resources, Avalonia manifest resources; see 15 — Development).

Key properties: net10.0 + net10.0-windows (dual target — the net10.0 TFM is Linux/macOS-only and rejects Windows RIDs via a build guard), Avalonia 12.1.4, UseWindowsForms=False, version synced to the WPF app (5.8.4), StartupObject = SimpleLauncher.Avalonia.Program.

• Reuses SimpleLauncher.Core for all business logic (launch, scanning, persistence, emulator config injection, RA).
• Windows-only services (#if WINDOWS, net10.0-windows): F8 global hotkey (AvaloniaGlobalHotkeyService), active-window screenshot (AvaloniaActiveWindowScreenshotService + WindowScreenshot Win32 helpers, System.Drawing.Common package conditional on the windows TFM).
• Cross-platform services: AvaloniaTrayIconManager (Avalonia TrayIcon + NativeMenu; icon\icon.ico copied to output), AvaloniaFilePickerService (platform-aware filters, dialogs parented to the active window), EmulatorConfigHandlerRegistration (the 21 pre-launch config handlers are registered on Windows only), AvaloniaDispatcherService, embedded JSON localization (manifest resources SimpleLauncher.Avalonia.Resources.strings.*.json sourced from SimpleLauncher.Core\Localization, 18 languages, 2671 keys each, all files in full key parity with strings.en.json).
• Remaining work is tracked in References/TODO.md. All 44 windows and 21 Inject* dialogs are headless-smoke-tested via AvaloniaViewSmokeTests (45 window + 21 inject tests); RetroAchievementsViewModel and RetroAchievementsSettingsViewModel have full unit coverage in both WPF and Avalonia (30 + 19 tests). The Linux regression suite pins every finding of the Linux review (LB-01 … LB-23) — see 14 — Testing.

SimpleLauncher/
├── App.xaml(.cs)            DI composition root, startup sequence
├── MainWindow.xaml(.cs)     + 12 partials (hosts, menus, pagination, search, close events…)
├── *.xaml(.cs)              22 root windows (About, Debug, EasyMode, EditSystem, InjectConfig…)
├── InjectConfigWindows/     21 emulator config-injection dialogs
├── Pages/                   Favorites, GlobalSearch, PlayHistory
├── ViewModels/              44 ViewModels (incl. 21 Inject*ConfigViewModel)
├── Services/                UI services, launch handlers, scanners, RA, favorites, play history…
├── Interfaces/              host & service interfaces (29)
├── Models/                  app-side models (SearchResult, WindowScreenshot, RaAchievement…)
├── resources2/              theme overrides (HighContrast, Midnight)
├── tools/                   bundled executables (see 11)
├── samples/                 emulator config templates (samples\{Emulator}\*)
├── audio/ images/ icon/     shipped assets
└── appsettings.json, app.manifest, mame.dat, parameters.md, WhatsNew.md

SimpleLauncher.Core/
├── Services/                ~30 areas (see 07 — Core Services)
├── Models/                  data models (Ra*, History, emulator settings, converters…)
├── Interfaces/              service contracts
└── (no UI, no XAML)

• 01 — Overview
• 07 — Core Services
• 11 — Bundled Tools
• 15 — Development