[bityard]

There is a Markdown spec: https://commonmark.org

Although of course in practice, commonmark renderers are not plentiful or up to date. In my experience, most library authors end up just implementing the bits of Markdown they care about and the behavior they prefer for the ambiguous parts.

[TheRealPomax]

There are multiple markdown specs. This is one of them, probably the most well-known, but certainly not the only one.

[alsetmusic]

“This is my Markdown. There are many like it but this one is mine.”

[wrboyce]

Obligatory https://xkcd.com/927/

[MrVandemar]

https://hn.algolia.com/?dateRange=pastMonth&page=0&prefix=fa...