The basic syntax outlined in the original Markdown design document added many of the elements needed on a day-to-day basis, but it wasn’t enough for some people. That’s where extended syntax comes in.
Several individuals and organizations took it upon themselves to extend the basic syntax by adding additional elements like tables, code blocks, syntax highlighting, URL auto-linking, and footnotes. These elements can be enabled by using a lightweight markup language that builds upon the basic Markdown syntax, or by adding an extension to a compatible Markdown processor.
Source: Extended Syntax | Markdown Guide
I have been using Markdown for a while. However, with my use of Obsidian, I have been exploring the extended syntax. I recently explored the addition of footnotes.
To create a footnote reference, add a caret and an identifier inside brackets ([^1]). Identifiers can be numbers or words, but they can’t contain spaces or tabs. Identifiers only correlate the footnote reference with the footnote itself — in the output, footnotes are numbered sequentially.
Add the footnote using another caret and number inside brackets with a colon and text ([^1]: My footnote.). You don’t have to put footnotes at the end of the document. You can put them anywhere except inside other elements like lists, block quotes, and tables.
Source: Extended Syntax | Markdown Guide
The problem I found was bringing this content back into HTML and WordPress. My usual Markdown to HTML translators (Code Beautify or Markdown Dingus) did not include footnotes. However, after testing a number of websites, I found that Dillinger includes extended syntax.
Jan Boddez