ext_wal_ prefix in place of the wallet ID to look it up. Prefix ext_wal_ to the external ID value to form the identifier.
For example, if a wallet has external_id set to order-12345, your app can reference it as ext_wal_order-12345:
ext_wal_ prefix works on all wallet endpoints that include a wallet ID in the path, including get wallet by ID, update wallet, and RPC endpoints.
When using authorization signatures, sign the request
using the URL exactly as sent, including the
ext_wal_ prefix.
