When working with System Center Configuration Manager (a.k.a. SCCM or ConfigMgr) you see a lot of folders on primary sites where all kinds of files pass through. Most of these are text files and you can open with notepad. The hard part is knowing what the file does, and where it goes next. Most see these folders as their final place before loading the info into the DB and then the file deletes, but some files move elsewhere to process.
I recently encountered an issue with a backlog of files on the CAS in hman.box. A lot can process through this folder, especially if you are connected ton Intune. In researching I found out an interesting piece of information I wanted to share. If you look at the file name you will see something like ABCUDXasdf234.MCM. This file name itself can tell you a lot. The first three letters are the site code of the destination for the file. In this example the file is headed for the ABC site. Once there the file will get renamed with the file extension of the next three letters, UDX in this example. Then you may need to do some sleuthing to figure out where it is headed. In my case I simply opened the file in notepad and got a clue, but if it wasn't that clear you could do some research on the file extension. In this example a UDX file is a user discovery file from Intune, so it is headed for DDM.box, specifically the ddm.box\userddrsonly folder.