Koodo Reader is a cross-platform ebook reader application supporting a wide range of formats (EPUB, PDF, MOBI, AZW3, TXT, FB2, CBR/CBZ, MD, DOCX, HTML, etc.). It is built as an Electron desktop app with a React/TypeScript frontend and a separate Go HTTP server for OPDS catalog serving and KOReader sync. The application provides a full-featured reading experience including bookmarks, notes, highlights, text-to-speech (with multiple voice engines), translation and dictionary lookup (via built-in and custom plugins), OCR for scanned PDFs, and cloud sync/backup across many providers (WebDAV, S3, OneDrive, Google Drive, Dropbox, etc.). It also includes a library management system with shelves, tags, search, and import from local files, folders, URLs, and OPDS catalogs. The architecture is a monolith with a clear separation between the Electron main process (Node.js) and the renderer (React), plus an optional Go server for network-facing features. The codebase is large and feature-rich but shows signs of technical debt: widespread use of deprecated React lifecycle methods, heavy reliance on opaque minified libraries (kookit-extra), frequent `as any` type casts, and mixed Chinese/English comments. Despite these issues, the application is actively maintained and offers a robust set of features for ebook enthusiasts.