Mastering: mAP50 {value_pct} at epoch {epoch} — three quarters of the way to a perfect score, or more.
Epoch {epoch}: mAP50 {value_pct}, a change of {delta_pct} points since the previous reading. Most of the distance to a perfect score is behind this run.
Far along: mAP50 {value_pct} at epoch {epoch}, at or within 1% of the best this run has reached.
