Where is the widget code and can it be edited?

I found an old thread asking where to edit the widget codes, but the answer no longer applies, as I assume paths and files have changed. Hence, my question.

I will just use the example readily available from the initial install with demo data.

Dashboard>Theme Options>Page Setup>Home Page>Content Elements>Categories (or any of the drag and drop blocks, actually)

Is this populated from a widget and its code? I want to change the landing page of the category/subcategory/whatever links to a specific page, or at the very least, understand from the code where it is going and what it is using to build the output.

I’m not new to WP, but am new to this theme and quite hopeful that it will be what we need for this particular project.

Thanks!