Footnotes now supported by GitHub's web interface

See the GitHub blog post Footnotes now supported in Markdown fields. Here is the HN discussion.

I verified that GitHub’s web interface renders and links footnotes in README.md files or any other .md file in a repo.

As of this writing the published GFM spec hasn’t been updated to reflect this. But the support added to cmark.gfm has been published:

Changes since last release (0.29.0.gfm.1...0.29.0.gfm.2):

  • Fixed issues with footnote rendering when used with the autolinker (#121),
    and when footnotes are adjacent (#139).
  • We now allow footnotes to be referenced from inside a footnote definition,
    we use the footnote label for the fnref href text when rendering html, and
    we insert multiple backrefs when a footnote has been referenced multiple
    times (#229, #230)
  • We added new data- attributes to footnote html rendering to make them
    easier to style (#234)

But from the change description it’s obvious that footnotes were implemented even earlier. Found it: Footnotes (pull request #64), from Nov 2017. But it was only deployed/enabled for GitHub Pages:

What is the timeline for this footnote extension to be enabled in GitHub or for gists?

There are no plans to enable the extension on GitHub.com or in gists. This is for Pages only.

It looks like it still doesn’t work in Gists (I tried with the Markdown Extra test file for footnotes).

And the following doesn’t render (but replace the list item’s * with a > and it’s fine):

Test.[^1]

[^1]:
    Test
    
    * List item