org-angle-link-re

org-angle-link-re is a variable defined in `org.el'.
Its value is

"<\\(doi\\|elisp\\|f\\(?:ile\\(?:\\+\\(?:\\(?:emac\\|sy\\)s\\)\\)?\\|tp\\)\\|https?\\|m\\(?:ailto\\|essage\\)\\|news\\|shell\\):\\([^]	\n
<> ][^]	\n
<>]*\\)>"

Documentation:
Matches link with angular brackets, spaces are allowed.