What does the EASY-column (percent) mean in the Browser?
I think you’re talking about ease.
it kinda shows how hard a card is (based on how many times you pressed each button).
new cards don’t have ease, but as soon as a card exits learning phase, anki gives it an ease of 250%
each time you press again on that card, its ease decreases by 20 percent
each time you press hard on that card, its ease decreases by 15 percent
and each time you press easy on that card, its ease increases by 15 percent
pressing good doesn’t affect the ease
pressing any button on card that are in learning and re-learning phase won’t change their ease.
lowest ease possible for a card is 130%
if you wanna read more about how exactly it does affect your card’s interval, you can read
Reviews part in this post.