MVVM layering inside a single WPF UserControl:
- `MacroBrowserControl.xaml/.xaml.cs` is the view; it wires AvalonEdit syntax highlighting (Python.Dark.xshd) and opens hyperlinks via `Process.Start`.
- `MacroBrowserViewModel : BaseViewModel` owns all UI state (`ObservableCollection<string>` for Authors/Eras/Shards/Macros, `Category` filter), exposes `RelayCommand`/`RelayCommandAsync` actions, and drives data loading on construction by invoking a `_data` dictionary of `Func<Task<string[]>>` entries backed by the singleton `Database`.
- `Data/Database` is a thread-safe singleton wrapping an in-process LiteDB file (`macros.db`) with three collections — `repository`, `manifest`, `macros` — plus an `HttpClient` and `GitHubClient`. It fetches `metadata.json` from the repo's raw URL, caches it for 15 minutes (or until the master branch SHA changes), and lazily downloads macro source text keyed by name+SHA1.
- `Models/` holds LiteDB-persisted entities (`Macro`, `Manifest`, `Metadata`, `Repository`) plus a `Category` used as a hierarchical filter value.
- `Data/Filter` + `FilterType` model the shard/era/author/category predicate applied against the manifest before returning macro names.
- `Controls/ClearableComboBox` is a reusable ComboBox extension exposing a `ClearCommand` DP bound to the ViewModel's `ClearCommand`.
Dependency direction: View → ViewModel → Data/Models; Models are pure POCOs decorated with `[BsonId]`; no cross-dependencies between sibling subfolders except ViewModel depending on both Data and Models.