The set of icons used. In this case the the icons are shown, in order, as:
- Shiv-able/Tranq-shot-able (ex: Warrior's enrage, rogue Shadow Dance)
- Spell Stealable (not yet implemented)
- Extra Dangerous (ex: Pally wings) <...
In this picture, you see that the target is marked as Dangerous (shown by the first large icon on the top of the screen), and Spell-Immune (shown by the second). The rogue here is using Shadow Dance and Cloak of Shadows, which is what the addon is c...