In http://testanything.org/tap-version-14-specification.html , there is a formatting error under the “YAML diagnostics” heading:

This seems to be caused by a Markdown processor that is configured to convert --- into a Unicode em dash (‘—’) and thereby somehow eating the backtick after the --- in the source document. Here's the relevant source fragment.

If a Test Point is followed by a 2-space indented block beginning with the
line `  ---` and ending with the line `  ...`, separated from the Test

One solution would be to use --- instead of backticks in the source document, to let it be treated as raw HTML. However, this will not have the desired result when generating output formats other than HTML.

I think the right approach is to configure the Markdown processor to not bother with translating --- into em dashes and instead configure your keyboard to easily type these directly, if so desired.