Refresh Token Inaccessible

[MIJohnson]

I'm using this plugin to authenticate using JWT and Oauth2 (via Keycloak)

There is a accessToken api call provided in the RestOauthController where a valid refreshToken can be provided to request/generate a fresh accessToken. But how is one supposed to retrieve/surface the refreshToken initially generated for the first AccessToken? I cant find any documentation on this, and looking at the source code it doesn't seem possible?

Pointers greatly appreciated