True Comp Duplicator v3 is an essential script for After Effects that automates the duplication of complex composition hierarchies, ensuring all nested sub-comps are duplicated independently so changes in one don't affect the original. How to Get It
Version 3 introduced several massive workflow improvements over previous iterations: Deep Hierarchies: true comp duplicator v3 free download
If you are looking for similar functionality without using this specific paid script, consider these options: True Layer Duplicator: True Comp Duplicator v3 is an essential script