Question
What devices are enumerated by the machine inventory?

Answer
 

MachInv uses the a windows API (which is believed to draw its data from the registry) to enumerate devices. AeXMachInv.exe does filter and only includes the following: 

• MFG of "Standard system devices"
• Enum of "Root"
• Enum of "PCIDE"
• Enum of "SW"
• Class of "Volume"
• Devices that have (C)ontroller, (F)irmware, or (B)ridge in the description.

If there are other devices that you wish to report, custom inventory can be implemented to retrieve data from the win32_systemdevices.partcomponent WMI class.