This POD contains a link to a built-in command, unlink.

NOTE that the test for proper handling of X<...> was expanded and moved to xt/author/perlpod.t, since it made reference to POD over which I had no control. I am very grateful to Zaki Mughal (zmughal) for diagnosing the problem, developing the fix, submitting the pull request, and rattling my cage after I, for reasons inexplicable to me, ignored all this for a couple weeks. An equivalent (I hope!) test using only files under my control was added by modifying t/data/_lib/mu.pod to add an X<...> after the AUTHOR entry, which is referred to by t/data/pod_ok/external_installed_pod.pod.