Good question. I don’t know, so I decided to try it out for myself.
My installation is Apache proxying requests to Tomcat/XWiki.
In my virtual host configuration for xwiki, I have the following:
<VirtualHost *:443>
ServerName info.example.com
So, I added a new domain to my VirtualHost configuration using ServerAlias, like so:
<VirtualHost *:443>
ServerName info.example.com
ServerAlias data.newexample.net
and restarted Apache.
Normally I access my wiki with https://info.example.comt/xwiki/bin/view/Main/ so I tried https://data.newexample.net/xwiki/bin/view/Main/ and it worked exactly as expected.
Just to be sure, I used the developer tools to check all the network requests to xwiki, and all of them were using the new domain.
So it seems like a very straight forward change with no hassles for a single apache proxied to tomcat, single instance xwiki installation.
Does that answer your question?