Optional damage, healing and threat meters. Switch any of them on under Settings > Interface. They share one small window you can drag anywhere, and closing it turns all three off.
Damage and Healing meters show each party member's total and per-second rate for the current fight (healing includes shield absorbs). When the fight ends, its numbers stay up until the next one starts.
Threat meter shows who the enemy you last hit wants to attack. Its current target sits at 100%. Your bar turns amber, then red, as you get close to pulling it onto yourself (110% of the target's threat in melee, 130% at range).
