These are codes set by the UN ECE for international trade. They can be used for more than just ports, for example airports also have a LOCODE. However, while airports also use an IATA code, the shipping industry refers to the LOCODE for ports as the primary identifier.
More information about LOCODE for shipping here:
https://www.freightos.com/freight-resources/seaport-code-name-finder/#:~:text=Any%20location%20used%20in%20international,shipping%20companies%20and%20freight%20forwarders.

Port list: https://freightanchor.com/resources-sea-ports-codes

Tracking by port code:
https://www.cogoport.com/en-IN/knowledge-center/resources/port-info/adelaide-auadl

https://www.marinetraffic.com/en/ais/details/ports/890?name=ADELAIDE&country=Australia

