diff -r 19d0e5efa6ca -r 7072b91ccd20 mercurial/help/hgignore.txt
--- a/mercurial/help/hgignore.txt	Sat May 16 16:25:05 2015 -0700
+++ b/mercurial/help/hgignore.txt	Wed May 20 14:54:09 2015 -0700
@@ -68,6 +68,10 @@
 and a regexp pattern of the form ``\.c$`` will do the same. To root a
 regexp pattern, start it with ``^``.
 
+Subdirectories can have their own .hgignore settings by adding
+``subinclude:path/to/subdir/.hgignore`` to the root ``.hgignore``. See
+:hg:`help patterns` for details on ``subinclude:`` and ``include:``.
+
 .. note::
 
   Patterns specified in other than ``.hgignore`` are always rooted.