How to analyze the value of `mode-line-misc-info'?

[Kevin Vigouroux]

#+begin_src emacs-lisp
ELISP> mode-line-misc-info
((global-mode-string
  ("" global-mode-string " ")))
#+end_src

I don’t understand why there are two nested lists. I thought the second
list was used as a conditional statement (e.g. `global-mode-string'
returns non-`nil') to finally concatenate several strings.

• Emacs Lisp Ref. manual — 23.4.2 “The Data Structure of the Mode Line”
- https://www.gnu.org/software/emacs/manual/html_node/elisp/Mode-Line-Data.html
-- 
Kevin Vigouroux,
Best regards