diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -2401,6 +2401,13 @@
     effect if ``HGPLAIN`` is set or ``HGPLAINEXCEPT`` is set and does
     not include ``tweakdefaults``. (default: False)
 
+    It is a way to opt-in to what the community has decided
+    is the "best" default experience for Mercurial
+
+    It greps our current directory instead of grepping every filelog
+    at all revisions and reporting the highest filelog revision that matches.
+
+
     It currently means::
 
       .. tweakdefaultsmarker