The following entries are needed for completeness:

{ kty: "RSA",
  alg: "RSA-OAEP" }
to:
{ name: "RSA-OAEP",
  hash: {name: "SHA-1"}
}
 
{ kty: "RSA",
  alg: "RS1" }
to:
{ name: " RSASSA-PKCS1-v1_5",
  hash: {name: "SHA-1"}
}
 
{ kty: "RSA",
  alg: "RSA-OAEP-256" }
to:
{ name: "RSA-OAEP",
  hash: {name: "SHA-256"}
}

It is true that the choice of "RSA-OAEP" to mean RSA-OAEP with SHA-1 as mgf is unfortunate, but that is what JOSE has adopted.