This is the header, located here: [app_root]/blueprints/www/templates/www/includes/header.html
[app_root]/blueprints/www/templates/www/includes/header.html
It's being imported in the [app_root]/blueprints/www/templates/www/extends/main.html template.
[app_root]/blueprints/www/templates/www/extends/main.html