Unknown source wp1a.org

Hello,
on my google search console I found some blocked resources on my wordpress page. This resources are from https://www.wp1a.org/jquery.js and it was surprising for my.
So I started to find in my wordpress core and plugins php, js, css, html files and in my database too, some clues about wp1a. But I found nothing !

Then I scanned source page in browsers and I found this:

<script type=”text/javascript” src=”https://www.wp1a.org/jquery.js”></script&gt;

Interesting is that this code was only on my homepage and it appears differently in browsers:

Firefox – code always occurs on homepage
Chrome – code occurs with first load of homepage, but after homepage reload code disappeared
IE and Opera – code never occurs on homepage

I do not know what is it ?
Please help.

Thanks