Do not hide link labels

Sorry but how can I not hide link labels? For instance

[bar]: "foo bar"

is turned into a link, but I want to keep the foot reference visible. What happens is that they are hidden instead, not rendered in the output.
Perhaps what I’m looking for is “footnotes”? How do I insert a footnote? The syntax [^1] does not seem to work.

I wished for that as well, at least for reference link definitions within list items or other blocks.

Depending on the processor and output format, you could still add footnotes in post-processing, though, but you will probably lose your explicit identifier bar. Some implementations also support a footnote syntax extension or of the box or via ready-made plugins.

The problem with 3rd party implementations or extensions that add their own syntax is that they break standardization, don’t they? Which is the topmost reason for using commonmark in the first place.