bug#51247: 28.0.60; Insufficient documentation of tab-bar.el internal functions

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 51247@debbugs.gnu.org
> Date: Mon, 18 Oct 2021 20:02:21 +0300
> 
> > Or let me turn the table and ask you to explain to a potential Lisp
> > programmer what to expect from adding a function to the list in
> > tab-bar-format.  Suppose J.R. Hacker wants to write a function
> > suitable for inclusion in this list, and suppose the function returns
> > a string or a list of menu items -- what should J.R. Hacker expect
> > from putting that function in this list? how will the tab bar display
> > the value returned by the function?
> 
> It will display tabs or buttons from these menu items.

When will it be tabs and when will it be buttons?  And to which of
these does "menu" belong?