custom-guess-name-alist

custom-guess-name-alist is a variable defined in `cus-edit.el'.
Its value is shown below.

Documentation:
Alist of (MATCH TYPE).

MATCH should be a regexp matching the name of a symbol, and TYPE should
be a widget suitable for editing the value of that symbol. The TYPE
of the first entry where MATCH matches the name of the symbol will be
used.

This is used for guessing the type of variables not declared with
customize.

You can customize this variable.

Value:

(("-p\\'" boolean)
 ("-flag\\'" boolean)
 ("-hook\\'" hook)
 ("-face\\'" face)
 ("-file\\'" file)
 ("-function\\'" function)
 ("-functions\\'"
  (repeat function))
 ("-list\\'"
  (repeat sexp))
 ("-alist\\'"
  (alist :key-type sexp :value-type sexp)))