SymfonyCloud includes an additional
X-Robots-Tag header on all
X-Robots-Tag: noindex, nofollow
That tells search engines to not index sites on non-production environments entirely nor traverse links from those sites, even if they are publicly visible. That keeps non-production sites out of search engine indexes that would dilute the SEO of the production site.
On a production instance (the master branch, after a domain has been assigned)
the search-blocker is disabled and your application can serve a
file as normal.