Description of problem:
There is a keystone upstram bug: https://bugs.launchpad.net/keystone/+bug/1703369
In this bug "identity:get_identity_providers" was used as default instead of "identity:get_identity_provider". The identity:get_identity_provider should be at singular (no trailing "s").
Same typo exists in Horizon unit testing and documentation and it is not yet fixed.
Version-Release number of selected component (if applicable):
Latest version in git source
$ grep -r get_identity_providers
openstack_auth/tests/conf/keystone_policy.json: "identity:get_identity_providers": "rule:admin_required",
openstack_auth/tests/conf/policy.v3cloudsample.json: "identity:get_identity_providers": "rule:cloud_admin",
The typo is fixed upstram: https://git.openstack.org/cgit/openstack/horizon/commit/?id=93bb571888a1bff4fa1e110356dbf2cb9fb4ee52
There are no mentions of that policy name in Horizon in OSP10, OSP11 or OSP12, so no backports for those versions are necessary.