In github readme.md file,top area have this syntax content

---
title: "something"
ms.date: "03/30/2017"
author: 
  - "somebody a"
  - "somebody b"
  - "somebody c"
description: somethings...
---

When github website preview this readme.md file,the convert to html table display.

What is this begin --- to --- end markdown syntax,is there CommonMark syntax?

.Net markdig can’t parse to HTML Table element.