ReferenceGrants
Resource Owner Password Credentials
Client collected the user's password and POSTed directly to the token endpoint. The user's password is in your app, defeats the point of OAuth2 delegation.
Resource Owner Password Credentials
Spec: RFC 6749 §4.3 (deprecated)
Supported in Olympus: No (deprecated; do not use)
When to use
Never. Removed in OAuth 2.1. Use Authorization Code instead.
How it works
Client collected the user's password and POSTed directly to the token endpoint. The user's password is in your app, defeats the point of OAuth2 delegation.
Why not
This grant is deprecated and removed in OAuth 2.1. Olympus rejects it. The replacement is Authorization Code + PKCE.