See title, you are not supposed to be able to use numeral ids in commands anymore, yet in some places it still works:

• Block with an item in it

  • setblock ~ ~ ~ chest default replace {Items:[{id:"1",Count:1b,Slot:0b}]}

• Mob with armor/tools

  • /summon zombie ~ ~ ~ {ArmorItems:[{},{},{},{id:"1",Count:1b}]}

• Item frames

  • /summon minecraft:item_frame ~ ~ ~ {Item:{id:"1",Count:1b}}

• Items

  • /summon minecraft:item ~ ~ ~ {Item:{id:"1",Count:1b}}

• Particles

  • /particle blockdust ~ ~ ~ 0 0 0 1 10 force @a 1

• Loot tables

  • {
        "pools": [
            {
                "rolls": 1,
                "entries": [
                    {
                        "type": "item",
                        "name": "1",
                        "weight": 1
                    }
                ]
            }
        ]
    }

• CanPlaceOn and can destroy (MC-50795)

  • /give @p command_block 1 0 {CanPlaceOn:["137"]}

Expected behaviour: none of the items exist as it's an invalid id.

Note: it has to be defined as a string, any other tag type won't work
Note 2: It might be a good idea to hide the numeral ids from F3+H as they shouldn't be used anymore.