Variable: help-xref-url-regexp
help-xref-url-regexp is a variable defined in help-mode.el.gz.
Value
"\\<[Uu][Rr][Ll][ \n]+['`‘]\\([^'’]+\\)['’]"
Documentation
Regexp matching doc string references to a URL.
Source Code
;; Defined in /usr/src/emacs/lisp/help-mode.el.gz
(defconst help-xref-url-regexp
(purecopy "\\<[Uu][Rr][Ll][ \t\n]+['`‘]\\([^'’]+\\)['’]")
"Regexp matching doc string references to a URL.")