cunnyborea-fe/static/error/404/404.conf

error_page 403 =404 /404.html;
error_page 404 /404.html;
location = /404.html {
        root /opt/cunnyborea/instance/static/static/error/404;
        internal;
        add_header Strict-Transport-Security "max-age=31536000; includeSubdomains; preload";
        add_header X-Content-Type-Options "nosniff";
        add_header X-XSS-Protection "1; mode=block";
        add_header X-Permitted_Cross-Domain-Policies none;
        add_header X-Frame-Options "self";
        add_header Referrer-Policy "same-origin";
        add_header X-Download-Options noopen;
}