Get scope list from X-OAuth-Scopes header

[ginjo]

According to Slack docs, the full set of authorized scopes for a token is returned with every api request in the X-OAuth-Scopes header. I can't find that information in the auth_hash returned from omniauth-slack. Is there a way to access that information - and info from other slack-specific headers - in the omniuath-slack oauth_hash, or maybe in the env? Would it make sense to include all slack-specific headers in the auth_hash? I do remember seeing a list of scopes somewhere, once, so maybe I'm looking in the wrong place.