I'm attempting to understand the difference between two methods for viewing a PDF stored within the repository via the Web Client. 

If I search for the document by entry ID, the document is auto-opened and served via this URL: 

https://server.domain.com/laserfiche/Docview.aspx?db=Repository&docid=1192412#?source=search&openmode=PDF

If I browse to it's parent folder and open, it's served via this URL:
https://server.domain.com/laserfiche/Docview.aspx?db=Repository&docid=1192412#?openmode=PDF

Both using "docview.aspx".  But my firewall is recording activity of the document being accessed via this URL:

https://server.domain.com/laserfiche/Viewer/Pdf/StreamingHandler.ashx?r=Repository&id=1192412

... using StreamingHandler.ashx... Which, if I but this URL directly into my browser, does load the document, albeit via a different interface. 

How is this StreamingHandler.ashx view invoked by  a user through the Web Client? I'm not able to trigger it's use through browsing or the auto-open that occurs from a search that returns a single result?

I would have assumed the StreamingHandler.ashx was invoked for serving MIME types like mp4 files and simliar, not for a PDF. 

We need to understand how/where it's being invoked by a user through the WebClient interface when serving a PDF.