This is the yield percentage that is currently being generated by the pool, based on the current TVL, current Curve Gauge boost that is active on that pool and rewards priced in USD. If all parameters stay exactly the same for a few weeks (TVL, CRV boost, CRV price, CVX price, potential 3rd party incentives), this will eventually turn into the current APR. As that scenario is very unlikely to happen, projected APR should be taken with a grain of salt. Similarly, all fees are already abstracted from this number.