How was 11 year old tape located in time?

I can see how TV networks would want to keep video of all the shows that they put on the air.  But the tape that did so much damage to The Donald was an out take, not broadcast video.  How come it was saved, and how did anyone find it 11 years later, just in time to do The Donald a lot of harm?  How much rummaging thru dusty boxes of video tape was required? And how much viewing of aged video was done, and by who? 
   There is a story here. Wanna bet the MSM won't touch it with a ten foot pole?  "All the news that fits, we print".