ON THIS WIKI
The XP Bucket is an item added by the OpenBlocks mod. This bucket of liquid experience can only be obtained by right-clicking a tank with liquid experience with an empty bucket. Unlike a lot of other liquids, the liquid experience can not be placed in the world, it can only be placed inside of compatible liquid containers by right-clicking them with the bucket, which then empties the bucket into the container.
20 mB of Liquid XP is equivalent to one experience point.