http://spec.commonmark.org/0.28/#autolink
Is the simple reason that none of the following relative (i.e. not absolute-URI) autolinks are supposed to be working, that it is too hard to distinguish them from HTML tags?
<directory/>
<file.ext>
</root/file.ext>
<./local/file.ext>
<../upper-level/file.ext>
<#target>
<?query>
Link titles are not explicitly supported in autolinks. Was that a deliberate decision, especially since internal whitespace is disallowed?
<long file.ext>
<me@privacy.net "My Name">
<http://example.com "standardized example domain">