Discovery

SEEING things, ie: Looking at blocks, Collecting XP, Picking up items from the ground, looking at players / mobs, seeing new biomes, worlds, and so on will all earn you XP

Current Discovery Skills:

Experimental unity

Collecting an Experience orb has a chance to give you random XP in any adapt tree! This is only up to 8 XP per by default but this is configurable

World Armor

This will search near you for blocks, any blocks that are near you are added to a pool calculation, you will gain armor that is permanent so long as you are near these blocks, stacks with armor, and dissipates as you leave or lower the average toughness of blocks (now you can build your house of obsidian and not feel bad!)

Experimental Resistance

Spending your XP will allow you to mitigate the damage you take from direct or indirect sources (this is a once in a while ability, best used if you are constantly being blown up, or are prone to falling!) Default cooldown is once every 15 seconds

Villager Attraction

This skill will consume some XP, and when you open the UI of a villager has a chance to give you better trades! Max level is a guarantee / less XP