You’re right, it’s confusing. I edited the wiki page.
There’s already a feature thread to improve the virtualhosts to avoid the confusion:
Zammad requires nginx and to run next to apache it needs to listen to another port. To make it work without using a non-default port I used a virtualhost name reverse proxy. A path reverse proxy (https://www.nethdomain.tld/zammad) didn’t work in my tests so only way was the virtualhost name reverse proxy and therefore a separate domain name is needed.