Why is ES6 code included in the assembly?

Question

JavaScript

Separated part of the application code into a separate module. I collected it with a webpack with babel. package.json says

"main": "dist/main.js",

The final code of the module does not contain ES6 code, but the code that connects this module from NPM already contains, for example, CONST and gives an error in the browser "syntaxerror use of const in strict mode". And already in this code, where my transpiled module is connected - in the code of this module there is a syntax with CONST, as if webpack did not take dist/main.js but immediately index.js from the root of the module sources.
Tell me, where am I connecting something incorrectly?