Variable: completion-pcm--delim-wild-regex
completion-pcm--delim-wild-regex is a variable defined in
minibuffer.el.gz.
Value
"[-_./:| *]"
Documentation
Regular expression matching delimiters controlling the partial-completion.
Typically, this regular expression simply matches a delimiter, meaning that completion can add something at (match-beginning 0), but if it has a submatch 1, then completion can add something at (match-end 1). This is used when the delimiter needs to be of size zero (e.g. the transition from lowercase to uppercase characters).
Source Code
;; Defined in /usr/src/emacs/lisp/minibuffer.el.gz
;;; Partial-completion-mode style completion.
(defvar completion-pcm--delim-wild-regex nil
"Regular expression matching delimiters controlling the partial-completion.
Typically, this regular expression simply matches a delimiter, meaning
that completion can add something at (match-beginning 0), but if it has
a submatch 1, then completion can add something at (match-end 1).
This is used when the delimiter needs to be of size zero (e.g. the transition
from lowercase to uppercase characters).")