I know the exp bar is on UI\Feedback\XpBar\XpBarConsole.mdx and I made a custom version with removed textures through magos model editor, but when I put it back on my map, it doesn't seem to load it (I presume it is loaded even before the map, but given its context - a map specific element not used anywhere else, I find it hard to fully believe).
I cannot seem to find any particular string that handles the current exp against the needed for leveling up (eg 10/200) shown when you put your mouse over the exp bar aforementioned. | 
