These are default folders:
- audible
- documents
- music
- system
These have to do with a font hack:
- font.properties.new
- font.properties.orig
- netfront.ini.new
- netfront.ini.orig
This is a file Calibre uses (delete it if you don't use Calibre on your computer)
This is probably the official firmware update downloaded over wireless (it looks like the file name is truncated):
I'm not positive, but I think this came from using Windows Media Player to transfer music to Kindle.
The official firmware probably won't install until you remove the font hack. (the newer versions don't have this limitation, but if you're seeing the update file just sitting there, you probably have an old style hack). If you don't know which font hack was installed, (you need to know this to remove it) click Menu > System and look at the firmware version at the bottom of the screen. Anything in addition to 2.5.x is a clue to which hack is installed.