What is this hole in the toilet bowl?

Hello,
I have won this new toilet bowl on eBay (wall-mounted hanging toilet). Now inside the bowl, where the water will later stand, there is a strange small hole with a diameter of about 2 cm (see picture).
What is this hole for?
What additional materials are needed to use this hole?

Greetings from Andreas

A nozzle can be installed in this hole, which is activated when the flush is operated and sprays a powerful jet into the toilet to flush it forcefully. These toilets are mostly found in the USA.

These toilets are mostly found in the USA.

Apparently, it's not just the portions that are bigger

larger firmer more compact

As long as no pressure washer is connected for dismantling!

*No daydreaming*

Hello,
I have won this new toilet bowl on Ebay. Now, inside the bowl, where the water will later stand, there is a strange small hole with almost 2 cm diameter (see picture).
What is this hole for?
What additional materials are needed to use this hole?

Greetings from Andreas

Hello Andreas,

you normally get these nozzles at specialist retailers (e.g. Richter and Frenzel) or you can order them online.
Just google it.
Best regards
Stefan