diff --git a/lisp/files.el b/lisp/files.el
index 2707a4e8bbe..246b17baa3f 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -6995,7 +6995,14 @@ arguments and should return a lambda that can restore a previous state
 of the buffer.  Then after reverting the buffer each of these lambdas
 will be called one by one in the order of the list to restore previous
 states of the buffer.  An example of the buffer state is keeping the
-buffer read-only, or keeping minor modes, etc.")
+buffer read-only, or keeping minor modes, etc.
+
+The default value restores the buffer's read-only state to what it
+was before reverting.
+
+Set this variable to nil to disable restoring any buffer state
+attributes from before reverting.  Then only the file from which the
+buffer is reverted will determine the buffer's state after reverting.")
 
 (defun revert-buffer-restore-read-only ()
   "Preserve read-only state for `revert-buffer'."