This is just the definition of a standard for dApps that are chain agnostic.
You could link one or more wallets to your decentralized identity (DID).
For example hive:beeab0de000000000000000000000000:josediccus (Hive) and eip155:1:0xab16a96d359ec26a11e2c2b3d8f8b8942d5bfcdb (Eth mainnet).

Once we have this standard in place and a method to provide Hive Authentication in Ceramic and/or other tools, we can have a Sign in with Hive button, along with Sign in with Eth or Btc, wouldn't it be cool?