Beta
How much you move when the market moves.
How it is computed here
Covariance with the index divided by the index's variance, over the days both series share.
Worked example
This one compares the portfolio with an index you choose, and the demo portfolio has none set — so there is no honest example to show here. On your own portfolio, choose a benchmark on the dashboard and it appears.
Where it misleads
It is exposure, not quality. And it assumes the relationship is as symmetric going up as going down, which it almost never is — the capture pair says more.