Custom Model Data

Minecraft supports adding Custom Model Data to various blocks and items. It would look strange if these custom blocks had the same descriptions as normal blocks, so Item Descriptions supports custom descriptions for these items.

Assuming you've set the value of a Carved Pumpkin's Custom Model Data to 1, you would add the following entry to your resource pack's language file (en_us.json for English U.S.).

"lore.minecraft.carved_pumpkin.custommodeldata.1": "Hello!",

For other items, you would use a similar description.

"lore.<item_namespace>.<item_id>.custommodeldata.<value_of_custom_model_data>": "<Description here!>",