The blueprint package is an item which is consumed when used and gives the player items from a loot table. It is given to players when they first join a world, unless disabled in the config. By default, this gives the player a pickaxe, shovel, and axe blueprint, as well as a random sword blueprint. You can change this by modifying the loot table. It is not restricted to just blueprints and templates, you can make it give the player whatever you like.

Loot Table

The default loot table is located at data/silentgear/loot_tables/starter_blueprints.json.

Customize Individual Items

You can also change the loot table on a specific blueprint package item by setting it in NBT, creating custom blueprint packages. Create a compound tag named silentlib.LootContainer, then a string tag inside that named LootTable. You probably do not want to do this, but it is an option.

Example using give command:

/give @p silentgear:blueprint_package{"silentlib.LootContainer": {"LootTable": "namespace:loot_table_name"}}

The default loot table would be silentgear:starter_blueprints for the LootTable tag.

Additional Info

When advanced tooltip info is enabled (F3 + H), the loot table is listed in the tooltip.