Pack format

pack_format, sometimes referred to as pack_version, is a version number used to group versions with compatible assets. This number is used in:
 * version.json
 * pack.mcmeta

Resources
This number is used to declare the format of a resource pack in pack.mcmeta. Below is a list of all valid formats with corresponding versions.

Data
This number is used to declare the format of a data pack in pack.mcmeta. Below is a list of all valid formats with corresponding versions.