ComposeFS should have been in F41, but it's postponed for F42. ComposeFS uses EROFS, so it should be whitelisted to make it work.

https://github.com/containers/composefs
https://blogs.gnome.org/alexl/category/composefs/
https://fedoraproject.org/wiki/Changes/ComposefsAtomicDesktops