host-apply.sh.
Environment
Saving.env also deletes bootstrap/cache/config.php, because a cached config ignores .env. The next deploy caches it again.
nginx
nginx is tested withnginx -t before every reload. A broken file is not applied and the error is shown on the page, so your other sites keep working.
Add extra location blocks (OAuth callbacks, Socket.IO, large uploads) directly in the editor. Keep this line inside every server { } block; it carries the Security tab rules and the Monitoring request log:
server_name when it is missing.