This addon works very much like Battleground Targets, but also functions outside of battlegrounds as well, for World PvP. When in battlegrounds, it will load the players at the start of the battle much like BGT does, and outside of BGs, whenever a hostile player is detected in the combat log, it will begin gathering information about that player trying to determine their spec, hp, class, etc. It will generate a frame for this player, including a health bar corresponding to their class color if known, a spec / class icon next to their name, and a frame for their PvP trinket's cooldown and DR on the target. All players detected will be displayed in a list of frames on the players screen.
If a player has not been heard from in the combat log for 30 seconds, the frame will be removed, assuming combat with that player is done. The frames slowly black out until removal, showing some indication to the user of which players they are actively battling, as they will be brightly colored.
The addon contains many options to resize the enemy player frames and customize what data shows up on the frames.