There's a card with the buttons named, and a few lines of small print on the back in silver grey print on grey, that is so short of contrast it's almost impossible to read in perfect light. 50% of the space is unused so a much larger font was possible. Hardly a mini user guide though - a card with one image and 3 or 4 sentences on the back.
Only other things in the box were a sticker or two, and a single sheet of absurdly microscopic print with warranty and regulatory info etc.
My recollection, which may be faulty as it's been a while, of the tips app is it included mostly bits of trivia but nothing particularly useful or substantive. Basically just tips - not especially surprising.
There's a mini user guide in every iPhone box.
Also, Apple includes the Tips app by default on iPhones, that continuously prompts about features, and guides on how to use them.