[Question] Which function is used internally to update the tab-bar?

[Rodrigo Morales]

I'm learning how to customize tab-bar. I want to know the function
that is used for updating the content of the tab-bar.

I've noticed that the content of the tab-bar is updated whenever I call
=other-window= (by default, bound to =C-x o=).I wrote the following
function which helped me identify the exact times at which the tab-bar
is updated.

#+BEGIN_SRC emacs-lisp
(defun my/f ()
  (format-time-string "%H:%M:%S.%N"))

(setq tab-bar-format
      '(tab-bar-format-tabs
        tab-bar-format-align-right
        tab-bar-format-global
        my/f))
#+END_SRC

While trying to find the relevant function, I found the function
tab-bar--update-tab-bar-lines. However, when I evaluate this sexp
(tab-bar--update-tab-bar-lines), the tab-bar of the current frame is not
updated.