Details on expires_at, expires_in, not_before_policy and refresh_expires_in attributes

Hello,

My Keycloak 26.0.5 server returns the following attributes along with the ID, Access and Refresh tokens:

  • expires_at
  • expires_in
  • not_before_policy
  • refresh_expires_in

I have searched but am unable to find any references to these attributes in the keycloak.org website. Did I miss something? Or is there some common understanding of their formats (and meanings, although I have a sense) and usage that I don’t yet have?

I would appreciate any guidance - many thanks in advance!