menuTab

One tab of the app menu (appMenu), the menu the pause action opens: Escape, a gamepad's Start, the on-screen Menu button and a headset's left menu button, in every profile and on every platform.

A tab is a <name>.menuTab/ folder whose init.luau returns its spec:

return {
    title = "Game",
    build = function(ctx)
        -- ctx.presentation: "desktop" | "phone" | "vr"; ctx.width, ctx.height:
        -- the room the body has inside the menu's frame.
        return { type = "vertical", children = { ... } }
    end,
    onCallback = function(id, data) end, -- every callback the body raises
    back = function() return false end,  -- one step back inside the tab
    onShow = function(ctx) end,          -- each time the tab comes on screen
}

title is text, or { key = "namespace.key", values? } for the catalog message the menu says in the player's language each time it draws. A new world's tab reads the library's app_menu messages that way.

The body is an ordinary widget tree, the one ui.registerScreen takes, so a tab looks the way its world draws it. The menu draws the frame around it: Resume (back to the world), Enter or Exit VR, Recenter in a headset, and the tabs, across the top on a desktop, along the bottom on a phone, and along the bottom edge of the panel in a headset.

Which tabs the menu counts is decided by where the asset lives:

• The world's own source (/source, outside libs/ and deps/): the world's tab, shown first as the World tab whatever the folder is named. A new world starts with one, menuTabs/game.menuTab, which the world rewrites for its game. A world with none shows its title, Resume and the way to another world.
• The built-in library: the engine's tabs, ZeroMind (@builtin::menuTabs.zeromind) and System (@builtin::menuTabs.system).
• Anywhere else, another library or the dependency tree of a world installed into this one: nothing. An installed world brings its content and no menu of its own.

Opening the menu pauses nothing: every world is shared, and keeps running. Menu tabs stay out of search.