JWT Signing: Why is Google the only JWT Service for JWT Signing Properties?

Is there a way to add custom JWT signing from the Service dropdown list other than the only Google service listed in the dropdown list? I am trying to create a jwt signing for auth0 but I am only seeing Google as Service from the dropdown list, am suppose to assume if I choose Google everything will work even tho I am trying to create jwt for auth0? Let me thanks in advance.

P.S. I will select Google either way and see what happens once I start linking it to Oauth then auth0 clientid and secret key.

@Teodor @patrick @George