NGX_HTTP_UPSTREAM_IGN_EXPIRES 427 src/http/ngx_http_upstream.c { ngx_string("Expires"), NGX_HTTP_UPSTREAM_IGN_EXPIRES }, NGX_HTTP_UPSTREAM_IGN_EXPIRES 4283 src/http/ngx_http_upstream.c if (u->conf->ignore_headers & NGX_HTTP_UPSTREAM_IGN_EXPIRES) {