Selfhosted Bootstrap CSS and JS problem

Good afternoon, I'm newbie to Bootstrap for Drupal 7
My problem is that my sites are located in an offline intranet network, so I ran into one problem

namely I downloaded Bootstrap template, activated it (but did not do it by default) then based on the internal folder starterkit - created my own template, copying it to the themes directory and renamed it , as well as the internal file THEMENAME.starterkit in the name of my sub-theme

then I activated my theme and made it the default one. When I opened the main page, I didn't see the expected appearance of Bootstrap framework, and this is not surprising, since there are no CSS and JS files. Why I downloaded the latest version 3.4.1 from the official site and took the files from there

bootstrap.css
bootstrap.min.css
bootstrap.js
bootstrap.min.js

then I put these files in the css , js directory of my sub-theme.
Next, in the theme settings, I specified jsdelivr - Custom instead of jsdelivr, and then I specified relative paths to files in the fields

After that the appearance of the main page became expected

But! then I noticed some small inaccuracies in the behavior of certain components, such as the Views pager with AJAX, Fieldset collapsible, and others.

And this behavior is not present on simplytest.me :/ when I went to the developer tool, I noticed that in addition to bootstrap. css and bootstrap.js is also loaded by drupal-bootstrap. css

Please tell me if I understand correctly that this drupal-bootstrap.css file is a style add-on for Drupal made specifically for the theme, and I also need to download it and attach it to my sub-theme?