Changing some settings do not have any effect

The README contains the following explanations for settings:

• “Remote Login” can be disabled. Useful if you’re hosting totally separate websites.
• “Permanent redirect” uses a 301 redirect rather than 302 to send visitors to your domain mapped site.
• “User domain mapping page” allows you to disable Settings->Domain Mapping that the user uses.
• “Redirect administration pages to network’s original domain (remote login disabled if this redirect is disabled)” – with this checked, if a user visits their dashboard on a mapped domain it will redirect to the dashboard on the non mapped domain. If you don’t want this, remote login will be disabled for security reasons.
• “Disable primary domain check. Sites will not redirect to one domain name. May cause duplicate content issues.” – ignore the primary domain setting on your sites. The same content will be available on multiple domains and may cause problems with Google because of duplicate content issues.

I am switching these settings on and off and then testing my site via primary domain, secondary domain and while using www and without www in the beginning. All of these tests are done using curl -I so see headers with response codes and redirect.

No matter what I do the site behaves always the same way. Could you please add some examples to the settings to elaborate what they are supposed to do?

Also when switching setting 3 on and off there is no user visible domain mappings under any settings visible at any time.

https://www.ads-software.com/plugins/wordpress-mu-domain-mapping/