From the links in the tweets at the very bottom of this post...

From the links in the tweets at the very bottom of this post .... i have found that Nuheara applied for certification to list in the US OTC Markets on the 20th May 2019 ...... and subsequently, Nuheara appear now to have listed on the US OTC Pink Market, as of 31st May with the company code of "WDCRF" .....

By listing on the US OTC Markets, Nuheara have effectively created a vehicle by which US investors's (who may be a bit wary of the ASX) can buy into/ invest in Nuheara, bypassing the ASX ...

Highlighted below is a brief description via Google of OTC Markets -

"What are OTC markets?

Over-the-counter (OTC) or off-exchange trading is done directly between two parties, without the supervision of an exchange. It is contrasted with exchange trading, which occurs via exchanges. A stock exchange has the benefit of facilitating liquidity, providing transparency, and maintaining the current market price."

Nuheara "WDCRF" overview, and Pink Open Market information links are below -

https://www.otcmarkets.com/stock/WDCRF/overview

https://www.otcmarkets.com/corporate-services/information-for-pink-companies