@daffy4u:
* The ScreenSaver last page won't work with anything except a specific very old FW revision. It's unlikely to be updated, unless someone with Java skills take a look at it again.
* The SS Timeout (there's an updated package in my fonts thread) will only work on FW 2.x. It's probably doable on FW 3.x, but I haven't found a satisfactory way to do it more or less cleanly.
* USBNet works on FW 2.x & 3.x, but I'd be very, very glad to *not* have any specific instructions about it on the WiKi, it's really not something one should use unless they know exactly what they're doing, unless one likes using a Kindle as an expensive paper weight...

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But to answer the question about what it's all about, it's mostly used to access the Kindle system (ie. give us a root shell), and do so wirelessly on the K3, which can be nice for some things (ie. wirelessly side-load books).
In short, it's an invaluable debugging tool for developpers, but given the fact that you can very, very easily mess your Kindle up with this, I wouldn't recommend this to the average joe

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