I found this today by chance: I visited the help file on
C-h f split-strings:
split-string is a compiled Lisp function in ‘subr.el’.
(split-string STRING &optional SEPARATORS OMIT-NULLS TRIM)
subr.el is underlined like a hyperlink and doing
RET with point on it opens the source code.
I copied it this section to a Markdown file and the text was still underlined. I did
RET with point on it and it also opened the source code!
I have these modes active in the document:
[(Markdown ElDoc Wrap Fill)]. If I type the same characters as in
‘subr.el’ (copy-pasting the quotes, which I don't have in my keyboard), it is not highlighted and
RET does not follow the link.
Including hyperlinks like this one in Markdown is the one thing where I see org mode as superior to markdown mode.
Is it possible to add my own links to other files in markdown mode?
Update: The ability to follow the link with
RET is lost when killing and yanking the text that contains
‘subr.el’., or closing and opening the buffer for the file, so I believe this is some special ability in Emacs that comes from copying text from a documentation file and not a feature of Markdown mode.