It looks like Apple accidentally (?) leaked the iPad version of Affinity Publisher. Eagle-eyed redditor Liberink spotted this very screenshot, in a collage of various apps you could run on your brand new iPad Air, and that sure does look like an Affinity app, and Publisher, at that.
Affinity Publisher has been out for Mac for quite some time. The other Affinity apps – Designer and Photo – are available for iPad, and great, I might add, but Publisher has been missing. Developer Serif did announce it, but they’ve been mum ever since. Here’s hoping the release is imminent, Affinity Publisher on a 12.9” iPad Pro sounds wonderful to me.