customize type spec not being followed?

[Rusi]

When I do C-h v: org-structure-template-alist

I see:
-----------------
org-structure-template-alist is a variable defined in ‘org.el’.
Its value is shown below.

<description>

Value: ((97 . "export ascii")
 (99 . "center")
 (67 . "comment")
 (101 . "example")
 (69 . "export")
 (104 . "export html")
 (108 . "export latex")
 (113 . "quote")
 (115 . "src")
 (118 . "verse"))
---------------------

Its definition pointed to from above is
----------------------
(defcustom org-structure-template-alist
  '((?a . "export ascii")
    (?c . "center")
    (?C . "comment")
    (?e . "example")
    (?E . "export")
    (?h . "export html")
    (?l . "export latex")
    (?q . "quote")
    (?s . "src")
    (?v . "verse"))
  "Structure completion elements.
This is an alist of characters and values.  When
`org-insert-structure-template' is called, an additional key is
read.  The key is first looked up in this alist, and the
corresponding structure is inserted, with \"#+BEGIN_\" and
\"#+END_\" added automatically."
  :group 'org-edit-structure
  :type '(repeat
          (cons (character :tag "Key")
                (string :tag "Template")))
  :package-version '(Org . "9.2"))
--------------------------

So my question: When the type says character why does it show as integer?