accessWidget does not interfere at all with a site’s source code. It works through JavaScript code that modifies the site only at the browser level for the end-user. This means no permanent changes are made to your site in any way, and if you remove accessWidget, it will be as if it was never installed.
In addition, accessWidget loads asynchronously. This means that the browser does not wait for it to load before displaying your site or allowing visitors to interact. As a result, accessWidget does not impact your site's loading times or optimization scores in any way.