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Good question

I just noticed that too. I've just installed a few utilities, so maybe it's one of them. Diskaid was one of them, and Onyx - have you installed anything recently?
 
System crash

Apparently according to some other forum answers it's a file that stores any leftovers if you do an unsafe shutdown (holding the power button).

Many say it's safe to delete it's contents if you don't want the contents, which will be mostly unsaved or recovered documents.
 
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