You should see a migration dialog like this, where is selects your asset and other referenced resourced from you content folder, like materials or module scripts.
Note that the Niagara folder is also there (because your system uses it), but not selected by default. You don’t need to select Niagara plugin content for asset migrations.
Thanks, I just wanted to confirm whether I needed the Niagara folder and ended up here. I found that using Version: 5.0.3-20979098+++UE5+Release-5.0 creating a simple fountain system and selecting migrate that the default is for the Niagara folder to be checked. Which was unexpected…