Baertram wrote: »

I'd try the turning off & on addons method until I find one that does affect that target frame but considering Bandits UI turns it on & off it's more likely to be that addon than not?

Yeah, if you turn of Bandits and the bar and effect is gone, it must have been either this bandits addon OR any addon that got a dependency on Bandits and automatically disables if you disable Bandits UI!

The only addon that shows a dependency in the Add-Ons menu in ESO on Bandits UI is Bandits Companions unless you mean another dependency that ESO wouldn't detect.

Okay so I tried further searching and googled "eso what do the outward moving <> on the enemy health bar mean" and the AI Overview says:
"In The Elder Scrolls Online (ESO), outward-moving arrows (<>) on a health bar generally indicate that the unit (whether it's you, an ally, or an enemy) has a buff increasing their Health Regeneration.
Outward-moving arrows (<>): Increased health regeneration.
Inward-moving arrows (><) ): Decreased health regeneration or a "Defile" effect.
Context for the Arrows:
If you see these on an enemy you are fighting, it means a restorative effect is active on them.
If they are on your own health bar, you have an active buff (like from a potion or Templar/Restoration staff ability) increasing your health recovery."
This reddit link confirms that "outward arrows mean you have increased regen, inward mean decreased"
but I never noticed them on my own healthbar or an enemies healthbar before and they're not appearing on the enemy healthbar that replaces the compass in combat.

I will have to do some tests. If this was part of the base game than would that affect Bandits UI additional target frame or enemy target frame wouldn't that be a known thing?