How does your site score on this audit?
Duplicate modules can occur via the following ways:
1) Same code from the same package
This happens when the same code is present in different files from the same package.
2) Similar code from similar packages
3) Same code from the different package
This happens when the same code is present in files from different packages.
How does GTmetrix trigger this audit?
If the wasted bandwidth exceeds 1 KB, this audit triggers.
How to fix this audit?
To fix this audit, use a tool like webpack-stats-duplicates to identify duplicate modules.
Note: This is an expert-level optimization