diff --git a/src/doc/style-guide/src/README.md b/src/doc/style-guide/src/README.md
index 2ad834f804bd0..75013bb3df980 100644
--- a/src/doc/style-guide/src/README.md
+++ b/src/doc/style-guide/src/README.md
@@ -19,6 +19,18 @@ Thus, there are productivity benefits to using a formatting tool (such as
 `rustfmt`), and even larger benefits by using a community-consistent
 formatting, typically by using a formatting tool's default settings.
 
+## The default Rust style
+
+The Rust Style Guide defines the default Rust style, and *recommends* that
+developers and tools follow the default Rust style. Tools such as `rustfmt` use
+the style guide as a reference for the default style. Everything in this style
+guide, whether or not it uses language such as "must" or the imperative mood
+such as "insert a space ..." or "break the line after ...", refers to the
+default style.
+
+This should not be interpreted as forbidding developers from following a
+non-default style, or forbidding tools from adding any particular configuration
+options.
 
 ## Formatting conventions