OXX bot operating

Has anyone noticed the operation of an OXX bot operating in the pre-open session only?

I only stumbled upon the bot by looking at all quotes in the pre-open. The 3 bids appear just after 10:00. It has been there for a number of months at least. It is designed to push down the price by offering to buy shares that have been placed "at market" and not a fixed price. Bids for a small number of shares (300 or 600) are placed at the highest current bid plus other bids for similar small parcels at the next 2 lower prices. The 3 bids are cancelled normally around 10:06.

I don't believe it has resulted in any sales due to the very closely held share register. I cannot remember any trades for 300 or 600 shares in the recent past. So why is it there?