What is a Markdown file?
Short answer
Markdown is a plain-text format that turns into HTML: # makes a heading, * or - a list, backticks code. CommonMark defines the core, and GitHub Flavored Markdown adds tables, task lists, strikethrough and footnotes.
Renderers disagree on the details: fences inside code, nested list indentation, raw HTML blocks and escaped characters. A long file with all of them is a quick regression test.
Anatomy of a Markdown file
# HeadingATX headings, one to six #```langFenced code blocks with a language| a | b |GFM tables with alignment- [x]Task list items[text](url)Links, autolinks and reference links[^1]Footnotes
What you can generate
- YAML front matter
- Tables with left, right and centre alignment
- Fenced code with ``` and ~~~, including a fence-like string inside
- Nested bullet and numbered lists, task lists
- Links, autolinks, reference links and images
- Block quotes, HTML blocks, footnotes
- Unicode, emoji and backslash-escaped characters
How to make one
- Open the Markdown generator, or start from a preset above.
- Set the size and switch on the edge cases you need; the preview and size estimate follow every change.
- Generate, then download. The file is made in your browser, and the same preset and seed always give you the same file.
Questions
The file uses CommonMark plus the GitHub extensions (tables, task lists, strikethrough, footnotes). Switch features off to stay within plain CommonMark.
No. Every link points at example.test, a domain reserved for testing.