https://roots.io/trellis/docs/installing-trellis/ and https://roots.io/trellis/docs/local-development-setup/
The wordpress_site.yml
file is canonical.
Quite literally it's the canonical key within the yml the defines the URL to get to localhost
There's some magic within the ansible playbook that amends the host DNS
If you need to change the url for whatever reason vagrant provision
. The vagrantfile will re-run the ansible playbook.
These docs are better than roots.io https://code.lengstorf.com/learn-trellis-wordpress-roots/#part-iv-start-a-local-instance-of-the-wordpress-site-using-vagrant