Goldmark is a CommonMark-compliant Markdown parser and HTML renderer written in Go, designed for high performance and extensibility. The v2 branch introduces a complete redesign with Go generics, a cleaner separation of parser and renderer, and more semantic AST nodes. The core library exposes a `parser` package with `New()` and `Parse()` to produce an AST, and a `renderer/html` package with `New()` and `Render()` to output HTML. Extensions (tables, footnotes, strikethrough, task lists, typographer, linkify, definition lists) are implemented via a well-defined extension pattern using `parser.Extension` and `html.Extension` interfaces, making it straightforward to add custom syntax. The architecture is a library rather than a standalone application; it has no CLI or server, but is used by many static site generators and other tools. The codebase demonstrates strong engineering practices: extensive test coverage (including CommonMark spec tests and fuzzing), benchmarking against the C reference implementation, and a modular design that abstracts parsing, rendering, and text handling. The v2 version is still maturing, with some breaking changes from v1 that may affect third-party extensions, but the core is robust and well-documented.