How to remove .JS influences from the main page while leaving the rest?

Question

JavaScript

There was a question about css .. now I understand what is true in css .. I apologize for the meticulousness ...

Good afternoon!
Link to the site - https://goo.gl/oh8zTe
Background stretched on the main page.
The point is in the file - /bitrix/templates/main/build.js
Apparently, in these lines:

a(["get_val","jquery"],function(a,b){b(function(){var a=b("html");a.hasClass("activities_page")&&b(".section_wrap .columns").each(function(){var a=b(this);!function(){var b=a.attr("data-background");b&&a.css("background-image",'url("'+b+'")')}(),require(["section_block_resize"],function(b){a.each(b)})})})})}(),function(){function a(){var a=Array.prototype.slice.call(arguments,0);"string"!=typeof a[0]&&a.unshift("pages/activities_subpage"),window.define.apply(this,a)}a.amd={jQuery:!0},/**

But it is not exactly.
If I somehow change them (and, alas, I’m not strong here), then the images from the site page /activities/ disappear.
I need to make sure that the image on the main page does not stretch to 1634px, but is displayed in the original size so that the site page /activites/ does not suffer.
Tell me where in this .JS code the size of the background of the main page of the site is registered. I don’t see the numbers there, I don’t understand what to prescribe there. JS never understood and turned to freelancers. Now there is no such possibility and there is no connection to the one who slammed .JS to me.
Please, help!

Answer 1

1 - You are looking at build. Look for the sources, otherwise everything will return with the next update of the code.
In addition, in build there is a big risk of screwing up and breaking everything. Because nichrome is not clear, he is also minified.
2 - It's not about this code. This one only works on the page /activities/
3 - Without source codes and for free, hardly anyone will help you