Xcode 13's DocC documentation archives can be hosted using a custom Apache .htaccess file as described in Distributing Documentation to External Developers and Host and automate your DocC documentation - WWDC21.
What are the steps to get that set up for the SlothCreator example project on a macOS / a M1 Mac so you can look at the documentation in the browser?
Get the SlothCreator example project and build the documentation archive in Xcode or the command line as described in Distributing Documentation to External Developers
Install httpd via Homebrew:
brew install httpd
Copy SlothCreator.doccarchive to /opt/homebrew/var/www/ (paths are for M1 Macs)
Edit /opt/homebrew/etc/httpd/httpd.conf:
Allow AllowOverride All for the DocumentRoot Directory
Enable LoadModule rewrite_module
Edit /opt/homebrew/var/www/.htaccess and use the example configuration as provided by Apple in Distributing Documentation to External Developers
Restart Apache: sudo apachectl restart
You should now be able to open http://localhost:8080/documentation/slothcreator/ and http://localhost:8080/tutorials/slothcreator/
Enjoy!