We are going to supplement our iOS app with a sticker pack. So I created a new target (Sticker Pack Extension), and pushed a dozen of stickers into Stickers.xcassets.
Everything works great without a line of code: stickers appeared in iMessage and looks good.
The only question: can I add any analytics onto usage of our stickers? To know how popular they are, how often users insert them into their messages, etc.
As far as I know, this is not possible.