Avast Uninstall - Strang .app is kept

Hello,

I have recently tried to check avast, just to look at what he would do, and everything.

I then uninstall it (using their uninstalling method), but I saw that a lot of folders are kept in Mac, and not deleted. So I have manually deleted it.

However, I found an avast.app that is kept under /Library/StagedExtensions/Applications/Avast.app

Is this normal? It is impossible to delete this .app even with sudo.

Many Thanks