One use case: you have a game or app, and want to publish rich promo screens for new features or in game events. Even to old versions of clients. We once built

One use case: you have a game or app, and want to publish rich promo screens for new features or in game events. Even to old versions of clients. We once built a tiny in-house framework for this, based on Lua (game downloaded a package of Lua script and image resources and displayed the promo). If there was something ready to use (and multiplatform - at least android and ios), we could have saved quite some development time.