The upper section is for uploading and downloading your Waypoints. Routes, and Trials USR file which resides in a protected area of storage. If you click the download button you end up with this:
This allows wireless transfers of this file directly to your device of choice instead of transferring it to an SD card and transferring it from the SD card to your device .... sweet
Basically these units are set up just like a smart phone or tablet. It runs Embedded Linux for ARM CPU's as it's core OS just like Android does, Also like Android, Lowrance has it's own custom GUI which gives it it's character but the hardware and storage memory is all controlled by the Linux OS. So just like an "Unrooted" or "Unlocked" phone or tablet the OS'es core file storage is protected from user access and you have a "home" directory that allows access to a small portion of storage for logging files, custom wallpaper, downloads from the Go Free website, etc. That's what the Logs section gives you access to. It's basically a simple FTP file server and when you click the "Logs" link you can see it's an FTP port. You can also access it via a FTP program by typing in the same IP address you used before and enter 21 as the port
Those folders are where you can download (or upload with a FTP program) your Sonar logs files and AIS files for those who have that addition to their system. If you click the parent-directory link it takes you up to the userdata folder which looks like this:
This gives you access to additional folders of interest like screenshots. Here's a little tip on how this undocumented feature can be used to many people's advantage. I can take a screen shot of something interesting I see on the finder. and then access it via my smartphone's web browser and then transfer the screen shot to Google + or Facebook or any other place you upload pictures. No messing around with transferring stuff to a micro SD card and then to my phone or tablet which is still tricky depending on the device.