This is a mod used as an addon to the Mine Mine no Mi mod created by Wynd to allow players to see their Haki Overuse as an overlay whenever you enter combat mode.
For this to work on servers, it'll need to be installed server-side, otherwise it'll only work on singleplayer.
You will need the original Mine Mine no Mi mod for this to work, located here
If you need any help with the mod, my Discord is: Drqonic#0674