How the gitlab-ci cache is working on docker runner? what is /cache directory? what is cache_dir? : <ol>
<li><p>How the gitlab-ci cache is working on docker runner? </p></li>
<li><p>What is /cache directory? </p></li>
<li><p>What is cache_dir?</p></li>
<li><p>Where and how files matching the <a href="https://docs.gitlab.com/ee/ci/yaml/#cachepaths" rel="noreferrer">"paths" in "cache" gitlab-ci.yml</a> are stored?</p></li>
</ol>
