Hellō, specifically, the Hellō Wallet, is an implementation of OpenID Connect (opens in a new tab), the same identity federation protocol used by Apple, Facebook, Google, and Microsoft.
The Hellō OpenID Configuration is at https://issuer.hello.coop/.well-known/openid-configuration (opens in a new tab).
NOTE: The Hellō Issuer is
https://issuer.hello.coop and is NOT
https://wallet.hello.coop. This simplifies a separation of concerns per the Hellō Protocol