The run is under way: mAP50 {value_pct} at epoch {epoch}, at or within 1% of its best so far.
Epoch {epoch}: mAP50 {value_pct}, a change of {delta_pct} points since the previous reading. The learning phase continues.
Learning: mAP50 {value_pct} at epoch {epoch} — the best this run has reached, or within 1% of it.
