This Babel plugin automatically inserts **#\_\_PURE\_\_** comments on top-level function calls and new expressions in assignment contexts, helping UglifyJS perform more efficient dead code elimination and reduce bundle sizes. It's primarily designed for library authors who want to ensure their code is optimized for tree-shaking, though application bundles can also benefit from the reduced output size. The plugin assumes top-level calls are side-effect-free, so caution is advised when using it in code that may produce side effects.