It's about You-Know-What in vault you-know-which.
7 seconds sound clip from the Harry Potter and the Sorcerer's Stone movie soundboard.
You can hear this line at 00:24:55 in the Blu-ray version of the movie.
Quote context
[...]
- And does Mr. Harry Potter have his key?
- Oh, Wait a minute. Got it here somewhere.
- Ha! Here's the little devil.
- Oh, and there's something else as well.
- Professor Dumbledore gave me this.
- It's about You-Know-What in vault you-know-which.
[...]