When is something a separate flavour?

[Zegnat]

Ghost’s Markdown is different from Gruber Markdown, e.g. it implements strikethroughs. But it does this with a modified Github Flavored Markdown system.

• Documentation (that is, a “guide”).
• Code, with clear mention of GFM.

Is this a Ghost flavour (“Ghost GFM”) or just “GitHub Flavored”?

[stuartpb]

If Ghost's intent is to support GitHub Flavored Markdown precisely - ie. if someone pointed out a case where Markdown in GitHub renders differently from Ghost, they'd fix it - then it's just another implementation of GitHub Flavored Markdown.

If Ghost has its own extensions - or if, in the event of a conflict, Ghost declared that their parse result is "right" and that GitHub's is "wrong" - then Ghost would have its own documented flavor with these differences.