use submodule

excalidraw/excalidraw-app/components/ExcalidrawPlusAppLink.tsx

@@ -0,0 +1,19 @@
+import { isExcalidrawPlusSignedUser } from "../app_constants";
+
+export const ExcalidrawPlusAppLink = () => {
+  if (!isExcalidrawPlusSignedUser) {
+    return null;
+  }
+  return (
+    <a
+      href={`${
+        import.meta.env.VITE_APP_PLUS_APP
+      }?utm_source=excalidraw&utm_medium=app&utm_content=signedInUserRedirectButton#excalidraw-redirect`}
+      target="_blank"
+      rel="noopener"
+      className="plus-button"
+    >
+      Go to Excalidraw+
+    </a>
+  );
+};