TwentySixteen header appears to include a sidebar?

Hi there,
I’m trying to make a custom front-page.php in a child theme of TwentySixteen. The first thing I wanted to do was get rid of the sidebar that’s appearing on the left side. After some troubleshooting, I see that the sidebar is being driven by the header include. I looked in header.php in the parent theme and can’t see where the sidebar is being pulled from. I obviously need to include the header in front-page. Do I need to put a new header in my child theme?

I’m obviously pretty new at this, so excuse any blind spots in my question. Thanks for your time, and looking forward to your ideas.
Bill