Variable: diary-icalendar-url-regexp
diary-icalendar-url-regexp is a customizable variable defined in
diary-icalendar.el.gz.
Value
"^[[:space:]]+URL:[[:space:]]*\\(?1:\\(?11:[A-Za-z][+.0-9A-Za-z-]*\\):\\(?12:[]!#-;=?-[_a-z~]+\\)\\)"
Documentation
Regular expression to match URL of an entry.
The full URL should be matched by group 1. The default regexp matches URLs on lines like:
URL: http://example.com/foo/bar
This variable was added, or its default value changed, in Emacs 31.1.
Source Code
;; Defined in /usr/src/emacs/lisp/calendar/diary-icalendar.el.gz