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/styles/jssPreset/jssPreset.js

@@ -0,0 +1,18 @@
+import functions from 'jss-plugin-rule-value-function';
+import global from 'jss-plugin-global';
+import nested from 'jss-plugin-nested';
+import camelCase from 'jss-plugin-camel-case';
+import defaultUnit from 'jss-plugin-default-unit';
+import vendorPrefixer from 'jss-plugin-vendor-prefixer';
+import propsSort from 'jss-plugin-props-sort';
+
+// Subset of jss-preset-default with only the plugins the MUI components are using.
+export default function jssPreset() {
+  return {
+    plugins: [functions(), global(), nested(), camelCase(), defaultUnit(),
+    // Disable the vendor prefixer server-side, it does nothing.
+    // This way, we can get a performance boost.
+    // In the documentation, we are using `autoprefixer` to solve this problem.
+    typeof window === 'undefined' ? null : vendorPrefixer(), propsSort()]
+  };
+}