The source code

    /**
     * @class Ext.form.DisplayField
     * @extends Ext.form.Field
     * A display-only text field which is not validated and not submitted.
     * @constructor
     * Creates a new DisplayField.
     * @param {Object} config Configuration options
     * @xtype displayfield
     */
    Ext.form.DisplayField = Ext.extend(Ext.form.Field,  {
        validationEvent : false,
        validateOnBlur : false,
        defaultAutoCreate : {tag: "div"},
        /**
         * @cfg {String} fieldClass The default CSS class for the field (defaults to <tt>"x-form-display-field"</tt>)
         */
        fieldClass : "x-form-display-field",
        /**
         * @cfg {Boolean} htmlEncode <tt>false</tt> to skip HTML-encoding the text when rendering it (defaults to
         * <tt>false</tt>). This might be useful if you want to include tags in the field's innerHTML rather than
         * rendering them as string literals per the default logic.
         */
        htmlEncode: false,

        // private
        initEvents : Ext.emptyFn,

        isValid : function(){
            return true;
        },

        validate : function(){
            return true;
        },

        getRawValue : function(){
            var v = this.rendered ? this.el.dom.innerHTML : Ext.value(this.value, '');
            if(v === this.emptyText){
                v = '';
            }
            if(this.htmlEncode){
                v = Ext.util.Format.htmlDecode(v);
            }
            return v;
        },

        getValue : function(){
            return this.getRawValue();
        },

        getName: function() {
            return this.name;
        },

        setRawValue : function(v){
            if(this.htmlEncode){
                v = Ext.util.Format.htmlEncode(v);
            }
            return this.rendered ? (this.el.dom.innerHTML = (Ext.isEmpty(v) ? '' : v)) : (this.value = v);
        },

        setValue : function(v){
            this.setRawValue(v);
            return this;
        }
        /**
         * @cfg {String} inputType
         * @hide
         */
        /**
         * @cfg {Boolean} disabled
         * @hide
         */
        /**
         * @cfg {Boolean} readOnly
         * @hide
         */
        /**
         * @cfg {Boolean} validateOnBlur
         * @hide
         */
        /**
         * @cfg {Number} validationDelay
         * @hide
         */
        /**
         * @cfg {String/Boolean} validationEvent
         * @hide
         */
    });

    Ext.reg('displayfield', Ext.form.DisplayField);