The mod only adds a couple of new weapons including the Hammer and Beacon Axe. It also includes new advancements for the player to achieve aswell as a few paintings, a new dimension and some old features added like the rose, cyan rose, nether reactor core etc.
There is also a new line of potions like the Milk Potion which acts just like the milk bucket and removes potion effects but can be now thrown to share with other people. You also now have a glow and haste potion which just gives the player those effects but now they are craftable.
ah yeas also the language of the advancements is probably unknown to most people.