The Target Status Bar appears at the top of the User Interface when a target is selected. The red center bar is a representation of the target's health. The small circle on the left indicates red for aggressive or hostile, brown for non-aggressive and various white emblems for NPCs that are friendly. With the exception of the opposing faction, the level will be displayed next to the circle emblem.
The frame surrounding the target status reflects the rating, the simpler the lower; the more ornate, the higher. Elite bars have double ended arrows on the right end of the bar. Knowing the rating is important to guage how difficult it will be to kill the NPC.
Additional Settings Edit
Additional information can be displayed, depending on the checked selections in the Options - Combat Settings. The distance to target, and view target's target are very useful in combat situations. To add these, open the <Options> (O), and chose the <Game Options> tab. Scroll to the bottom, and on the right side choose the desired options. Click <OK> or <Apply>.