Cyberduck is a mature, multi-protocol file transfer client for macOS, Windows, and Linux (CLI). It supports over 30 storage protocols including S3, SFTP, FTP, WebDAV, Azure, Google Drive, Dropbox, Backblaze B2, and many more. The architecture is a Java core library with platform-specific UI bindings: Cocoa for macOS (via Rococoa/JNA), WinForms/WPF for Windows, and a command-line interface (duck). The core defines a clean set of feature interfaces (Read, Write, Find, Delete, etc.) that each protocol module implements, enabling a uniform file operation model. The system also integrates client-side encryption via Cryptomator vaults, which wrap protocol features transparently using decorator patterns. Key external dependencies include Apache HttpClient, JSch (SSH), and various cloud SDKs.
AnExplorer is a native Android file-manager application (package dev.dworks.apps.anexplorer) that exposes a Storage Access Framework-compatible DocumentsProvider layer over many storage backends: external/internal storage, USB OTG, root shell, FTP/FTPS, cloud storage (Google Drive, Dropbox, OneDrive, Box via CloudRail), app management, zip archives, recent files, and a note editor. It is a heavily customized fork of AOSP DocumentsUI: the core browsing state-machine, document stack, roots cache, recents persistence, and loader/cursor stack are AOSP-derived, with substantial product-specific additions for monetization, multiple build flavors, PIN security, settings, and Wear OS/TV support. The marketing site in web/ is a static Firebase-hosted page, not part of the application logic. The architecture is a classic Android monolith: Activities and Fragments drive the UI, Loaders and custom Cursor wrappers feed RecyclerView adapters, and each storage backend is implemented as a DocumentsProvider ContentProvider. Main entry points are DocumentsActivity and StandaloneActivity for browsing, plus the provider authority intents for the Storage Access Framework. External dependencies include AndroidX, Firebase Analytics/AdMob/Crashlytics, CloudRail, libaums for USB, Apache Commons Net for FTP, and an in-app billing library. Quality is mixed. The provider and cursor abstractions are reasonably flexible and a few utility components are genuinely reusable, but the codebase carries heavy technical drift: AGP 3.3 alpha, targetSdk 28, deprecated android.app.Fragment/AsyncTask/PreferenceActivity usage, duplicated flavor-specific classes, hardcoded ad and analytics identifiers, and third-party SDKs that are no longer actively maintained. It remains a functional, feature-complete consumer app rather than a modern engineering showcase.