Tracking Log??

Took me a while to find the one for my 2595 because the name on mine is UIStats.log.

You can view it with any text editor like Notepad.

It seems to me that it is a track of the "user interface" - that is, the various screens/buttons that you have gone through recently.

<DataType>
 <Name>UIStats</Name>
 <File>
  <Specification>
   <Identifier>STTS</Identifier>
  </Specification>
 <Location>
   <Path>.System/Logs</Path>
   <BaseName>UIStats</BaseName>
   <FileExtension>log</FileExtension>
  </Location>
  <TransferDirection>OutputFromUnit</TransferDirection>
 </File>
</DataType>

If the log concerns you can safely delete it's contents. I think you made a typo and left out the L in UStats.log
I did this to my own 2460 after reading your post.
It appears the log updates itself every day since my time stamp was today’s date. I looked at my original file I received with the unit and the date stamp was
11/29/11 at 1KB size.
The file today was date stamped as 4/22/14 with the size of 374KB.

I backed up today’s file and then went in and deleted everything below the line that displays "Header _End".

I turned the Nuvi on and checked all settings and everything remained the same and was not modified.
So it's safe to say you can delete the contents of the file without any ill effects.
But ALWAYS have a backup of any file you may wish to delete or alter.

In the 3490, I found something similar in .System\Logs\UISats.log.