Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/node_modules/@mui/system/esm/useThemeWithoutDefault.js

@@ -0,0 +1,12 @@
+'use client';
+
+import * as React from 'react';
+import { ThemeContext } from '@mui/styled-engine';
+function isObjectEmpty(obj) {
+  return Object.keys(obj).length === 0;
+}
+function useTheme(defaultTheme = null) {
+  const contextTheme = React.useContext(ThemeContext);
+  return !contextTheme || isObjectEmpty(contextTheme) ? defaultTheme : contextTheme;
+}
+export default useTheme;