Have you ever been in a situation where you just fought the wither, only to have the nether star fall into fire and be lost forever? Me neither, but I'd like to stay on the safe side.
This mod prevents items from being destroyed by fire or other damage sources (such as cacti or explosions). By default, the nether star will receive this treatment. Which items are immune can be easily configured!
1.15+
To make an item invulnerable, add it to the item tag fireproofitems/items/fire_proof_items. By changing the whitelist setting in the server config, these items will instead be the only items that are not invulnerable.
1.12
To make an item invulnerable, add the item ID to a new line in the txt file in the config.