Open Stack

I could not find any example/usage of v3tokenlessauth, using
environment variables. There are no documents to be found.

I assume we could need to have this one at least:
export OS_AUTH_TYPE="v3tokenlessauth"

What other environment variables are required if using this auth type?
Would like to use HTTPs x509 auth.

This is the only relevant doc found:
https://docs.openstack.org/keystone/train/admin/configure_tokenless_x509.html

[keystone_authtoken]
memcached_servers = localhost:11211
cafile = /etc/keystone/ca.pem
project_domain_name = Default
project_name = service
auth_url = https://192.168.0.10/identity/v3
auth_type = v3tokenlessauth
certfile = /etc/glance/certs/glance.pem
keyfile = /etc/glance/private/glance_private_key.pem

But there are no environment variables mentioned in the above doc.