What is "http://s7.addthis.com/js/250/addthis_widget.js" script?

[Note: remember to include site URL, ZC version, list of plugins, PHP version, etc ... read the Posting Tips shown above for information to include in your post here. And, remove this comment before actually posting!] So ebay recently sent a message saying:

"Starting in October 2017, Google Chrome—the browser used by almost half of all eBay buyers—will begin displaying the message "Not Secure" in the address bar when users visit standard HTTP pages or HTTPS pages that include non-secure HTTP content."

So, I remember something about settings to make my whole zencart size https secure, and I went to includes/configure.php and changed define('HTTP_SERVER', 'http://www.mysite.com') to define('HTTP_SERVER', 'https://www.mysite.com').

Then I went to mysite using chrome, and clicked around a bit and see the "S" as well as a shield icon and red x in the url bar of chrome, so I click on the 3 dots, more tools, developers tools, concole, and see:

Mixed Content: The page at 'https://www.mysite.com/index.php?main_page=product_info&cPath=1_2&products_id=1' was loaded over HTTPS, but requested an insecure script 'http://s7.addthis.com/js/250/addthis_widget.js'. This request has been blocked; the content must be served over HTTPS.

So using the developers tool kit and searching it looks like this "http://s7.addthis.com/js/250/addthis_widget.js" is part of a free template that I installed.

I'm guessing that I can simply delete the line:

"Line #172 : <script type="text/javascript" src="http://s7.addthis.com/js/250/addthis_widget.js#pubid=xa-4ff326d22d3b21a9"></script>"

?

Opps, forgot to delete first line, sorry!

You ask what is it, it is a tool that basically offers an interface to just about every social media outlet that there is so that a visitor can share your page's content or supposedly you can make it possible to distribute content to your visitor.
It's not part of Zen Cart, but rather probably from a plugin you've added or came with the template you installed.

Really all that was necessary (seeing that you have now removed the line) was to modify the link to go to https: instead of http:... the comment text remains in the source code even though the "option" is not presented...
So all you would have to do is modify for something like:

"Line #172 : <script type="text/javascript" src="http[B]s[/B]://s7.addthis.com/js/250/addthis_widget.js#pubid=xa-4ff326d22d3b21a9"></script>"

It's not exactly like that as I recall, but if you had previously searched using the developers tool kit you know where it is/was/should be. Realize now that by deleting it, you have, for no apparent reason, affected users that weren't using Chrome and didn't know any better about some reported mixed content that a single browser has chosen to use.