MarkText is a cross-platform desktop markdown editor (Electron + Vue 3) powered by the Muya WYSIWYG engine. It provides real-time rendering of CommonMark, GFM, and extended syntax including KaTeX math, mermaid/plantuml diagrams, footnotes, tables, task lists, and 30+ themes. The monorepo contains four packages: `desktop` (Electron shell with IPC, preferences, spellcheck, export), `muya` (TypeScript core editor with block-based state, snabbdom rendering, undo/redo via ot-json1, clipboard, and floating UI components), `muyajs` (legacy JavaScript engine, still present for partial feature parity), and `website` (Next.js documentation site). The architecture follows a block tree pattern where each block type (paragraph, heading, list, table, etc.) is a subclass with consistent parent/content interfaces. Communication between the Electron main and renderer processes uses typed IPC channels. The codebase demonstrates strong software engineering practices with extensive unit and e2e test coverage (Playwright, Vitest), reproducible builds (pnpm monorepo), and a focus on regression testing for edge cases. However, the ongoing migration from the legacy `muyajs` engine to the new `muya` engine introduces some code duplication and technical drift, and some modules retain prototype-style JavaScript alongside modern TypeScript classes.