This is put there as part of the process by which drivers/devices create child devices, which I assume is just internally how the platform handles getting the name of the child device from the app or driver that created it (it's not really documented, but if you specify a name and/or label as documented when creating the child device, the information also ends up there--besides also being the name or label). This is of no consequence after creation; the actual name or label, above, is what you'll see in the UI.
The text of a log entry is determined entirely by the driver, but the most common convention is to use the "display name" of the device as one of the first pieces of text, which will be the label if present, otherwise the name. (This is for the log entry itself; for the "heading" where you see app or device names, that should reflect the current name for live logs or the oldest past name still in use if viewing past longs.)
That being said, the text in your screenshot doesn't match the current display name for any of your devices as far as I can see. If you're looking at past logs, you should know that you'll see whatever the log text was at the time of its creation--not what you'd see if a new entry were generated now (e.g., in live logs). Could that explain the difference here?
You change the device name and label with the "Device Name" and "Device Label" fields under the "Device Information" section on the device page (towards the top/middle). The information you see under "Device Data" is not usually useful for end users, and the "name" and "label" you see there are not the ones that you should see anywhere else in the UI (again, this is not documented but based on my experience seems to be part of how child devices get created).
The source code for built-in drivers is not available (except for a few examples Hubitat published on their GitHub). Hubitat is mostly a proprietary, closed-source platform.