Variable: org-tag-group-re
org-tag-group-re is a variable defined in org.el.gz.
Value
"[ ]+\\(:\\([[:alnum:]_@#%:]+\\):\\)[ ]*$"
Documentation
Regexp matching the tag group at the end of a line, with leading spaces.
Tags are stored in match group 1. Match group 2 stores the tags without the enclosing colons.
Source Code
;; Defined in /usr/src/emacs/lisp/org/org.el.gz
(defconst org-tag-group-re
(format "[ \t]+%s[ \t]*$" org-tag--group-enclosed-re)
"Regexp matching the tag group at the end of a line, with leading spaces.
Tags are stored in match group 1. Match group 2 stores the tags
without the enclosing colons.")