Where is documentation that is described handleItemChange?

In the following page,  handleItemChange is used.

https://community.aras.com/f/development/5711/how-can-i-set-a-null-value-with-window-handleitemchange

I want to know handleItemChange  method detail.

I found out a description of this method on the following page.

cylnote.blogspot.com/.../windowhandleitemchange-method-instance.html

I think this page is not aras web site.

Is there a aras's documentation that is described this method ?