within Istio. It is primarily concerned with enabling Mixer
adapters to make decisions about who is allowed to do what.
In this template, the &ldquo;who&rdquo; is defined in a Subject message. The &ldquo;what&rdquo; is
defined in an Action message. During a Mixer Check call, these values
will be populated based on configuration from request attributes and
passed to individual authorization adapters to adjudicate.</p><table class=message-fields><thead><tr><th>Field</th><th>Type</th><th>Description</th><th>Re