strange font information in local abbrev table

[Uwe Brauer]

Hello 

I use the following simple functions


(defun ediff-copy-to-register-A ()
  (interactive)
  (copy-to-register ?A (region-beginning) (region-end) nil)
  (message "diff is copied to register A"))

(defun ediff-copy-to-register-B ()
  (interactive)
  (copy-to-register ?B (region-beginning) (region-end) nil)
  (message "diff is copied to register B"))

(defun ediff-define-abbrev ()
  (interactive)
  (let ((name (get-register ?A)))
        (let ((expansion (get-register ?B)))
          (define-abbrev local-abbrev-table  name (downcase expansion))))
  (message "abbrev is added using register A and B."))

Which come in handy for example to define abbrevs when ediff was called,
but could be used in other circumstances. Now while this works in Xemacs
and GNU emacs, I just recently discovered that in GNU emacs there is
some additional font information, whose origin and purpose I don't
understand:
example:

I have the defined the following minor mode with a corresponding 
abbrev table:

(deutsch-minor-mode-abbrev-table)
however when I defined 

hallllo to be expanded has hallo 

It works but relevant entry in the local-abbrev-table is:

#("hallllo" 0 7 (fontified t)) 0 "hallo"

The doc of define-abbrev seems not to make reference to this.

Can anybody enlighten me please?

Thanks 

Uwe Brauer