[nicoburns]

The problem here is that if you use ``` as a token in a non-markdown language, then it's going to be very hard to embed that code in a markdown code block. That problem doesn't happen with other syntax as it's already escaped by the code block. `---` inside a markdown code block will render as a literal `---`.

[yencabulator]

To embed content with multiple sequential backticks, use more backticks than the max run.

[nicoburns]

In theory, yes. But not all markdown implementations support this properly.

[yencabulator]

The CommonMark spec even has an example test case! The excuses for poor implementations are pretty thin.

[lilyball]

Not all markdown implementations are CommonMark

[yencabulator]

There's not much reason to be anything else than CommonMark + extensions.

[lilyball]

For new implementations, sure. But it's harder to change existing implementations (anything not already CommonMark-compatible will introduce unexpected changes to existing content if you switch to CommonMark), and especially for anything that's not being actively developed it's unlikely to ever change.