The 1.21 update for introduced several features focused on realism and gameplay tracking. Key highlights mentioned in community discussions include:

: Suggests that the total update or mod is split into multiple parts (e.g., part1, part2, part3) due to large file sizes.

The file name you provided follows a common pattern used in digital distribution, particularly for large updates or community-made mods: : Indicates the game version (1.21).

The update allows players to see animals as young deer, providing an opportunity to "mark" them on a notepad or toolkit to track their growth over time.

An or note included by the person who uploaded the file.

: A common archive file format used to compress data. You will typically need all parts (part1, part2, and part3) in the same folder to extract them using software like WinRAR or 7-Zip. Note on "Long Paper"