The Site Kit plugin acts as a “facilitator” between WordPress sites and the Google services that you choose to connect with your site. The only code that the Site Kit plugin itself adds to the front-end of your site is a meta tag, which you’ll notice below when checking your site’s source code:
<meta name="generator" content="Site Kit by Google [plugin version]" />
For each connected Google service, Site Kit will also add the appropriate code snippets on the front-end to allow for requests between the service and your WordPress site. If you choose to connect to AdSense, Site Kit will place the code to display ads, as well.
Site Kit adds these snippets as per each service’s recommended placement. Site Kit makes the same
http requests that are made when such Google services are connected manually. Integrating Analytics, for example, will result in an
http request to Google Analytics, whether you implement Google Analytics manually or via Site Kit.
In the back-end of your site, Site Kit adds code to enable its own functionality, including managing connections to Google services, service dashboards, and more. This does not impact your site’s front-end performance, as these operations only occur in the WordPress administrator panel.
We take reports of issues with site performance very seriously. If your site is experiencing slowness or other performance issues with Site Kit installed, please create a new topic on our support forum so that we can take a look.