IT'S IN THE NAME BRUV!
But yeah in all seriousness, all it adds is a Steak banner pattern.
The Steak banner pattern replaces the "Thing banner pattern", which is crafted with an enchanted golden apple. It also adds this texture to shields.
To get this texture, use white dye, if you use any other dye it will have a colour effect.
Also adds some other banners btw but those aren't important