Variable: nnheader-numerical-full-files
nnheader-numerical-full-files is a variable defined in nnheader.el.gz.
Value
"/\\([0-9]+\\)\\(\\.Z\\'\\|\\.bz2\\'\\|\\.tbz2?\\'\\|\\.\\(?:tgz\\|svgz\\|sifz\\)\\'\\|\\.g?z\\'\\|\\.lz\\'\\|\\.lzma\\'\\|\\.xz\\'\\|\\.txz\\'\\|\\.dz\\'\\|\\.zst\\'\\|\\.tzst\\'\\)?"
Documentation
Regexp that matches numerical full file names.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/nnheader.el.gz
(defvar nnheader-numerical-full-files (concat "/" nnheader-numerical-files)
"Regexp that matches numerical full file names.")