Long text and value

Hi experts !

Iu2019m creating asset with transaction AS01. Next Iu2019m entering into long text, where there are signs: CNK84216BD.Where from ? I donu2019t know. How I can remove them, without entering into field and deleting.

Thereu2019re probably default value. I havenu2019t any defined long text templates and assigned to Asset Classes.

Rgds Stenwa