TOOLTIP_LINES = {}
local nextLine = true
local container
PopupTooltip:AddControl(WINDOW_MANAGER:CreateControl("MY_CONTROL", PopupTooltip, CT_LABEL))
local container = MY_CONTROL:GetParent()
while nextLine do
   local nextLine = select(3,container:GetAnchor(0))
   if nextLine == PopupTooltip then break end
   table.insert(TOOLTIP_LINES, 1, nextLine)
   container = nextLine
end
 
--inspect lines using the /zgoo TOOLTIP_LINES

local function CheckChildren(control)
    for i=1, control:GetNumChildren() do
        local c = control:GetChild(i)
        if c then
            local type = c:GetType()
            --do something, like GetText if the control is a CT_LABEL
            CheckChildren(c)
        end
    end
end
 
CheckChildren(PopupTooltip)