Chunk Activity Tracker

The mod stores a heatmap of player activity by chunk. For every player it keeps the seconds spent in each chunk and the count of blocks placed in each chunk, so other mods can read where activity concentrates in a world. On its own it changes no gameplay; it provides utilities that mod developers call from their own code.

An optional setting keeps the unmodified heightmap of each chunk as it was first generated, which can be used later as a reference. The data is held in an optimized binary storage format that stays simple to read and write. The author reports stress tests with 100k chunks.

Installation needs Fabric API and TxniLib, and the mod is built for Fabric, Forge and NeoForge. Only the server needs it, so players join without installing anything. Builds exist for 1.20 – 1.21.1, with 1.0.1 as the latest file for each loader, and the mod is released under a custom license, not open source. Source code and an issue tracker are publicly linked.