Datapak is an archive that puts it in a world folder. It changes the game without mods: new biomes, constructions, recipes, achievements, mechanics. A downloader like Fabric is not needed, and on the server, the date pack works even if the players have a normal game.
Datapacks are divided into three types:
- change the world - Terralith, Tectonic, Incendium, Nullscape. They are placed only in a new world: they cannot be removed from the world later;
- change mechanics - VeinMiner, Dynamic Lights, Spawn Animations, True Ending. They can also be added to an already created world;
- add targets — BlazeandCave's Advancements Pack with thousands of achievements.
Many projects on Modrinth come out as both a datapack and a mod - the essence is the same, but the mod has settings that the datapack does not have.