Check out
Using two of the command show in the support guide yields the following results
% dig michelhotel-sonnenhof.de NS +trace | tail -n 6
michelhotel-sonnenhof.de. 86400 IN NS dns4.p01.nsone.net.
michelhotel-sonnenhof.de. 86400 IN NS dns3.p01.nsone.net.
michelhotel-sonnenhof.de. 86400 IN NS dns1.p01.nsone.net.
michelhotel-sonnenhof.de. 86400 IN NS dns2.p01.nsone.net.
;; Received 142 bytes from 2001:8d8:fe:53:0:d9a0:522d:100#53(ns1045.ui-dns.com) in 361 ms
Here, Netlify didn’t answer the query
Also whois shows non-Netlify nameservers too.
% whois michelhotel-sonnenhof.de | grep -i 'server'
Nserver: ns1028.ui-dns.de
Nserver: ns1045.ui-dns.com
Nserver: ns1049.ui-dns.org
Nserver: ns1062.ui-dns.biz