Markdown is lightweight markup for READMEs, docs and CMS content — headings, lists and code fences.
Markdown converts plain text conventions (# headings, **bold**, `code`) to HTML. CommonMark and GitHub Flavored Markdown (GFM) differ on tables and task lists.
Docs sites, GitHub and Notion all ingest Markdown. Tentaco Markdown Preview renders locally — preview README changes before push without a local Ruby/Python stack.