Chunk Activity Tracker is a simple library mod that tracks information about player activity for each chunk, mainly how much time they spend in them.

This mod does nothing on its own, but provides utilities to mod developers.

Features:

Tracks how much time, in seconds, each player spends in each chunk.
Tracks how many blocks each player places in each chunk.
Optionally, stores initial unmodified heightmap data for each chunk for future reference.
Optimized binary storage format, simple storage per-dimension in world save folder (stress tested with 100k chunks)