Xcode / iOS:Launchscreen.storyboard只能在Objective-C中进行编辑吗?

When I create a new iOS project in Xcode with its language set to Swift, I get two playgrounds from the single-view template. For some reason, when I open Main.storyboard using the Assistant editor, I can edit it in Swift, but when I do the same for LaunchScreen.storyboard it seems to open a file in Objective-C.

Why is that? Can LaunchScreen.storyboard not be edited in Swift or am I opening the wrong file when I select LaunchScreen.storyboard and open it with Editor -> Assistant?