Kubernetes auth role policies vs token_policies

Hello, in https://www.vaultproject.io/api-docs/auth/kubernetes#create-role, documentation says lists token_policies as an argument, but uses policies in the sample.
if I specify policies, token_policies is set with the same value, but if I set token_policies, policies is not.
what is the difference between these 2 fields? which one should I use?
thanks