[Eightt]

Found it here.

-----------------------------------------
--         Coordinate System           --
-----------------------------------------

function EH.UpdateCoordinates()
    local mouseOverControl = WINDOW_MANAGER:GetMouseOverControl()

    if (mouseOverControl == ZO_WorldMapContainer or mouseOverControl:GetParent() == ZO_WorldMapContainer) then
        local currentOffsetX = ZO_WorldMapContainer:GetLeft()
        local currentOffsetY = ZO_WorldMapContainer:GetTop()
        local parentOffsetX = ZO_WorldMap:GetLeft()
        local parentOffsetY = ZO_WorldMap:GetTop()
        local mouseX, mouseY = GetUIMousePosition()
        local mapWidth, mapHeight = ZO_WorldMapContainer:GetDimensions()
        local parentWidth, parentHeight = ZO_WorldMap:GetDimensions()

        local normalizedX = math.floor((((mouseX - currentOffsetX) / mapWidth) * 100) + 0.5)
        local normalizedY = math.floor((((mouseY - currentOffsetY) / mapHeight) * 100) + 0.5)

        EsoheadCoordinates:SetAlpha(0.8)
        EsoheadCoordinates:SetDrawLayer(ZO_WorldMap:GetDrawLayer() + 1)
        EsoheadCoordinates:SetAnchor(TOPLEFT, nil, TOPLEFT, parentOffsetX + 0, parentOffsetY + parentHeight)
        EsoheadCoordinatesValue:SetText("Coordinates: " .. normalizedX .. ", " .. normalizedY)
    else
        EsoheadCoordinates:SetAlpha(0)
    end
end

Where can I find documentation for these functions?
http://wiki.esoui.com/Raw_globals_dump
I see many addons using them but can't seem to find out how to use them.