My branch for ?trail also includes path
and path_natural sort orders, which sort the entire page name,
e.g. "a a/z ab ab/c b", much like map.
I used path as the default order for the
?trailitems directive,
since it seemed the most sensible.
(?trailinline uses
age as its default, to be consistent with inline.)
It's one commit (including a regression test) which can be
cherry-picked if you don't want the rest of trail.
--smcv