[O] [babel] What is `, (backquote comma)?

[Thorsten]

Hi List, 

in org-babel-expand-body:scheme (and
e.g. org-babel-expand-body:emacs-lisp) I encounter something like this:

(lambda (var)  (format "%S" (print `(,(car var) ',(cdr var)))))
        
While this part
`(,(car var) ...)
is explained in the manual (backquote and unquote), this part
`(... ',(cdr var))
is a bit mysterious to me, and I do not find information about
backquote( ... backquote comma ())
in the manuals or the web.

Is that Emacs Lisp? What does that mean?
Cheers
Thorsten