ThemeProvider: Document wrapper customization scope

packages/theme/CHANGELOG.md

@@ -10,6 +10,10 @@
 
 -   Mark the published `design-tokens.css` file as side-effectful so downstream bundlers preserve the documented CSS import ([#79551](https://github.com/WordPress/gutenberg/pull/79551)).
 
+### Documentation
+
+-   Document that `ThemeProvider` does not accept wrapper customization props ([#79763](https://github.com/WordPress/gutenberg/pull/79763)).
+
 ## 0.17.0 (2026-06-30)
 
 ### Breaking Changes

packages/theme/README.md

@@ -89,6 +89,8 @@ The `cornerRadius` prop sets the overall roundness preset for the theme subtree.
 
 When the `color`, `cursor`, or `cornerRadius` prop is omitted, the theme inherits the value from the closest parent `ThemeProvider`, or uses the default value if none is inherited.
 
+`ThemeProvider` does not accept wrapper customization props such as `className`, `style`, `as`, `render`, or `ref`.
+
 ### Nesting Providers
 
 The provider can be used recursively to override or modify the theme for a specific subtree.

packages/theme/src/types.ts

@@ -59,6 +59,12 @@ export interface ThemeProviderSettings {
 	cornerRadius?: CornerRadiusPreset;
 }
 
+/**
+ * Props for the `ThemeProvider` component.
+ *
+ * The provider's wrapper element is intentionally not customizable and does
+ * not accept props such as `className`, `style`, `as`, `render`, or `ref`.
+ */
 export interface ThemeProviderProps extends ThemeProviderSettings {
 	/**
 	 * The children to render.