On a SP2016 on-premise farm, I am editing a HTML Master page. I want to hide the gear icon from everyone beside the site admin. In my previous experience in older version, I can modify the Master page, wrap the gear icon part with something like
"<SharePoint:SPSecurityTrimmedControl runat=”server” Permissions=”ManageSubWebs”>".
However in the HTML Master page I cannot find anything like SharePoint:MenuItemTemplate. In the paired Master page, I also cannot find it. I can find SharePoint:MenuItemTemplate in seattle.master. I cannot find it in seattle.html. When I try to modify any master page, SharePoint prompt "This file may not be moved, deleted, renamed, or otherwise edited."
What is the best practice to achieve my goal?