It represents both a buy and a sell. Remember, in order for a...

It represents both a buy and a sell. Remember, in order for a trade to occur there must be a coming together of a buyer AND a seller.
If you're really asking what the 'XT' designation means, it's a cross trade in which a broker matches/executes ('crosses') a buy order and a sell order for the same stock placed by different clients within that broker's client group. It's routine and happens all the time. If you scroll through the Course of Sales list for almost any liquid stock for any given day you'll see it happening time and time again -- esp. with dominant retail brokers in Oz like CommSec who have a very large retail client pool.