Attach old wine barrel with glass plate

That may be true in a childless retiree household, but as soon as there are children in the house, I wouldn’t put a loose glass plate on an old wine barrel.

So what? Since the children are then no longer small enough to reach the wine barrel, the plate can’t tip over but would rather have to be pulled away (which can be prevented with rubber pads), the argument about children is not an argument at all.
You surely wouldn’t put glass bottles or glasses on any tables either. Nor plates or other fragile things? And so on.

The folks without children and grandchildren again...
When a 15kg glass plate slams down, it's significantly more dangerous than a glass or a carafe.
And I've never seen a coffee table where the glass plate just lies loosely on top, without a frame or something like that.

In this respect, the approach of fastening is already the right one.

How about gluing? There is special glue for something like that... Front windows of cars glued to the body, glass on metal, not screwed, not clamped, and certainly not just laid in loosely.

The guys without children

You can't mean me with three children and corresponding experience.

And a coffee table where the glass top simply lies loose on it, without a frame or something like that, I haven't seen yet.

And that's why ypg wrote to choose a suitable glass top for the recess to INSERT.

And that is why ypg wrote to choose a suitable glass plate for the recess for INSERTION.

Yes, but that was not intended at all. He was asked for tips on how to attach it on top. If you lay the plate in the barrel, you still have an edge. And the plate is smaller than the barrel, so impractical. I would also use these screw fastenings.

If you put the plate in the barrel, you still have an edge. And the plate is smaller than the barrel, so it's impractical. I would also use these screw fasteners.

Exactly .. and somehow that doesn't seem to be well received either, so you can also think about other solutions.