Hi Dana,

This middle number is the internal language ref (lngref) value of the publication output object that gets published.

From your sample folder name you should be able to verify this by looking at the contents of the metadata file of your publication object (GUID-536483FC-B5AA-491D-8DFB-15DD3900E56D.met)
Within this file you will see the value '792101' as the value of the attribute 'ishlngref' available on the ishobject element.

Do keep in mind that this naming convention will disappear as of SDL Tridion Docs 13 SP1 as the publishing code is reworked. So from that version onwards, the folder created during a publishing request is just a random string, not containing any reference towards the publication that is being published.

Kind Regards,
Raf

Hi Dana - To allow you to assess and prepare, this is what we currently have on the test bench for Tridion Docs 13 SP1 (13.0.1)

• Up to 13/13.0.0 it was a path like C:\InfoShare\Data\PublishingService\Data\DataExports\GUID-8966AB1A-26A0-470F-909A-FD38EED5831C.22128866.20170411121926696 so 122 chars 
• Starting from 13SP1/13.0.1 it will be C:\InfoShare\Data\Publish\Data\3zufoxj5cfs so 43 chars, or 79 characters more space. In the root of this folder we will offer a "*.publish.xml" file (e.g. "Publication MP330=GUID-.........=2=PDF (A4 Manual)=en-US.publish.xml") that will hold extra publication info.

We hereby mitigate the fixed Windows OS path depth limitation of 260 characters where some setups run into.