Documentation for webkit

I have been searching Google for that last 15 minutes trying to find Documentation on "webkit". What I'm looking for is official documentation on file.webkitSlice.

I was using file.slice on Chrome, but I guess an update *nixed that. I'm just trying to update some code.

I found webkit.org, but the main documentation refers to the actual build of webkit.

I guess this is the closest we are getting: https://developer.mozilla.org/en/DOM/Blob

according to Webkit JavaScript Reference