Homebrew What do these UI files mean in Smash Ultimate?

[Skythor25]

Hi. I've been getting the hang of modding my switch and have started modding my games, smash ultimate being the main one. As I looked through mods for a new start screen, I noticed they all came with a msg_menu.msbt file and layout.arc file. I was wondering what each of these did because when I get these title screens to work, they always have the smash ultimate logo during the opening. I made my own opening video and put it in, but the white smash ultimate logo gets in the way and was wondering if there was a way to remove that. I found a mod that got rid of the logo, but the title screen that was supposed to accompany the mod didn't appear, so I was going to try using another mod for the title screen. Which file would I have to swap to change only the title screen, or do the files work only with the ones that come with it?