https://ripple.com/wiki/Transaction_Format#AccountSet_.283.29 defines a field "WalletLocator" (256 bits) in Ripple's AccountSet transaction. That means that the field belongs to an account, and the owner of the account can set this field to whatever value they want.
Currently, it's not yet implemented in the client code but in the server code. I'm not able to make sense of the name "WalletLocator", and the code doesn't provide an explanation either.
What's the purpose of the field?