I have been using my Screen and Entity specific development in order to manage file attachments need and I see your add-on might be useful here. I have a couple of questions :
Can this add-on be attached to Editor screen in addition to browser screen you mentioned? For example, In my Sales order Editor screen, I have a separate tab to display attached documents and preview. Therefore, when the user is creating the Sales order, can attach relevant document before it is saved or can add/modify later.
How the Entity Attachment is associated with the main Entity at database level?