Why aren't edits being made to files in the Vendor folder?

Question

Laravel

I use Unisharp Laravel CKeditor, I want to fix the config so that the CodeSnippet plugin works (more precisely, it was by default, I want to add a code button to the Toolbar).
I edit js config files, nothing changes, I completely downloaded CKeditor from the office. site (I made an assembly using a builder with many plugins), replaced all files and folders, nothing has changed.
It's cached somewhere, I can't figure out where.
In ckeditor.js entered "123"

/*
123
Copyright (c) 2003-2018, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/

I open ckeditor.js in the browser.
I don't see what I entered. Cleared the cache and tried different browsers.
What can be wrong?