Hacker News Reader

Is there a name for those ##number## codes? It's been years since I had to use one of them to fix some random issue on a phone.

USSD and MMI, see for example https://en.wikipedia.org/wiki/Unstructured_Supplementary_Ser... . On a quick glance the references did not seem to list what codes are usually available, so just search "ussd code list" or similar.