What is a NB! file? (some type of video)?

Question

What is a NB! file? (some type of video)?

Answer 1

http://www.fileinfo.net/extension/nb

Read and enjoy

Answer 2

I was also searching for what an 'NB!' file is. It seems to be some sort of incomplete intermediate file that eventually becomes a .rar file when it's complete.

It has nothing to do with Mathematica

Answer 3

It's a file newer versions of NewsBin uses to begin work on fixing incomplete downloads and unraring them. I just noticed the other day that NewsBin had started to grab PAR files automatically, and that I no longer need to unrar my downloads.