Find Minecraft ID for non-item structures?

Does jmd know how to find out the ID for items / structures that have no hitbox and can't be included in the inventory?

The extra leaves of the Better Foliage Mod can z.b. With F3+ H not targeted and can't be included in the inventory. But I need the ID to integrate them into my shader pack so that they move like the normal leaves…

Better Foliage is purely client-side and purely visual. Nothing is changed and consequently there are no additional IDs. The symbol of barriers in Minecraft also has no own block ID.