mercurial/helptext/hgignore.txt

--- a/mercurial/helptext/hgignore.txt	Sat Jun 13 11:57:58 2020 +0200
+++ b/mercurial/helptext/hgignore.txt	Fri Jun 12 14:22:34 2020 -0700
@@ -95,3 +95,9 @@
   # switch to regexp syntax.
   syntax: regexp
   ^\.pc/
+
+Debugging
+=========
+
+Use the ``debugignore`` command to see if and why a file is ignored, or to
+see the combined ignore pattern. See :hg:`help debugignore` for details.