It's not weird!

It's the table's memory address! If you want to print each child name traverse the table returned or use unpack()

local ModelChilds = workspace.Xmodel:GetChildren();

for _, child in ipairs(ModelChilds) do
    print(child); --// print each child name
end

--// or \\--
print(unpack(ModelChilds));

You are also trying to call a nonexistent function :Destroy() on the table itself and not the children.

Just use :ClearAllChildren() if you need to delete just the children

workspace.Xmodel:ClearAllChildren();

The Name From what research I did, I found that that's the hex for the table, based upon this question on stackoverflow.

The Code When you want to destroy children that're in a table, you need to use a for loop to iterate through said table. A for loop (I'm speaking of a generic for loop), it returns two values: the index, and the value for said index.

local ChildrenInModel = Model:GetChildren()
for _, v in next, ChildrenInModel do
    print(v.Name, 'is in table!')
end

Side note; when attempting to use a method on a table, such as Destroy, it can look pretty weird when you look at it like this;

local ChildrenInModel = {Part1, Part2, Part3, etc...}

ChildrenInModel:Destroy()

-- Another way to look at it is

{Part1, Part2, Part3, etc...}:Destroy()

Stuff touched on

1. For loops - A loop that counts up or down depending on the values given to it.

2. Generic For loops - A for loop that iterates through a table that returns the index for its first value, and the value for the index. (I recommend reading up on it for a better explanation.)

3. Destroy - Pretty self explanatory. :p

If you have any questions, feel free to ask. :) I hope this helped! :D

GENERAL PRACTICE

Use :WaitForChild() to make sure a part / model exists before it is defined or changed

Use local rather than global variables as they are more versatile. (ex. "local model =" instead of "model =")

ISSUES

In order to destroy all of the children of "Xmodel" you need to iterate through the table using a for-loop (in pairs automatically gives you the instance of the child)

The print of a table will not return the children instances, but instead will give the actual table instance you've created.

REVISED SCRIPT

for i, v in pairs(workspace:WaitForChild("Xmodel"):GetChildren()) do
    v:Destroy()
end

You can also use :ClearAllChildren() however, any connections you have regarding these children will be kept, and not disconnected, so :Destroy() would be preferred.