h1-mod/data/ui_scripts/extra_gamemodes/__init__.lua

if (game:issingleplayer() or not Engine.InFrontend()) then
    return
end

Cac.GameModes.Data = {
    Standard = {
        Label = Engine.Localize("@MPUI_STANDARD_CAPS"),
        Image = "h1_ui_icon_playlist_standard",
        List = 
        {
            "dm", "war", "sd", "dom", "conf", "sab", "koth", "hp", "gun", 
            "dd", "ctf" -- missing gamemodes from UI
        }
    }
}