[woodruffw]

Microsoft might be steaming ahead on it, but I think GitHub’s extensions to Markdown predate their acquisition by a few years.

[WalterGR]

Correct on the latter.

GFM (Github-flavored Markdown) - "In 2017, GitHub released a formal specification of their GitHub Flavored Markdown (GFM) that is based on CommonMark." (https://en.wikipedia.org/wiki/Markdown)

Microsoft acquired Github in 2018.