diff --git a/jupyterlite_xeus/add_on.py b/jupyterlite_xeus/add_on.py
index 981d6d0..363e1a6 100644
--- a/jupyterlite_xeus/add_on.py
+++ b/jupyterlite_xeus/add_on.py
@@ -331,7 +331,7 @@ def pack_prefix(self, kernel_dir):
         # Pack JupyterLite content if enabled
         # If we only build a voici output, mount jupyterlite content into the kernel by default
         if self.mount_jupyterlite_content or (
-            self.manager.apps == ["voici"] and self.mount_jupyterlite_content is None
+            list(self.manager.apps) == ["voici"] and self.mount_jupyterlite_content is None
         ):
             contents_dir = self.manager.output_dir / "files"