[Krofh]

Nope, just the last name you had. It doesn't do anything weird with or permanent with the signature, it just adds the last username they had to the end.
For example, if my username was Billy, and now I have changed it to Krofh, my signature will have this line at the end of it:
"Formerly known as Billy."
In the case of me personally, it would look like:
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My hacks - Quote Notification - Prevent Multiple Registrations From Same IP Address - Profile Privacy
Available for custom hack coding for 3.5.x, drop me an email or PM
Formerly known as Billy
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Like I said, there really isn't much to this hack at all, it's just something I custom-made for my site and decided to put up here in case anyone else found it useful. I doubt more than three people will actually use it, ever.