|§cR§6a§ei§an§2b§bo§3w §aXP bar.zip release||79.10 KB||Apr 18, 2020||1.15.2||22,228||Download|
The only thing this pack does is that it makes your XP bar rainbow. That's it, that's the add-on.
OptiFine is recommended, but not needed. (the only thing it allows me to do is modify the colour of the XP level number)
Since this is an add-on, you'll need to place it above the faithful pack in the resource pack menu.